MEGOURA VICIAE BUCKTON
MARGARET BURNS
A t h e s i s s u b m it te d to
th e U n i v e r s i t y o f Glasgow f a r
th e d e g re e o f D o c to r o f P h i lo so p h y
i n th e F a c u l ty o f S c ie n c e .
D epartm en t o f Z oology ,
The U n i v e r s i t y ,
Glasgow W2. 1971
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CONTENTS
ACKNOWLEDGEMENTS
INTRODUCTION
RESULTS
( a ) F l i g h t b e h a v io u r
( b ) A c t i v i t y o f a p t e r a e
( c ) B e h a v io u r o f i n d i v i d u a l
a l a t a e b e f o r e f l i g h t
( d ) S iz e o f co rp u s a l l a tu m i n
t e n e r a l f l i e r s and n o n - f l i e r s
( e ) L ig h t and e l e c t r o n m ic ro sco p e
s t u d i e s o f f l i g h t m uscle
( f ) R e p ro d u c t iv e r a t e s and w e ig h ts
o f l a r v a e
(g ) R e s p i r a t i o n r a t e s
(h ) A l a t a p r o d u c t io n by a l a t a e
DISCUSSION
SUMMARY
REFERENCES
APPENDICES
ACKNOWLEDGEMENTS
The work d e s c r i b e d h e re was c a r r i e d o u t i n th e
Z oology D epartm en t o f Glasgow U n i v e r s i t y
d u r i n g th e t e n u r e o f two F a c u l ty Of S c ie n c e
S c h o l a r s h i p s aw arded f o r s e s s i o n s 1968 - 19&9
and 1970 - 1971 and th e Glasgow U n i v e r s i t y o
D onaldson S c h o la r s h i p f o r s e s s i o n 1969 - 1970«
I would l i k e to th a n k P r o f e s s o r D.R. Newth
f o r th e f a c i l i t i e s made a v a i l a b l e to me. I am
in d e b te d to Dr A .F .G . Dixon f o r h i s g u id an ce
and en co u rag em en t .
My th a n k s a l s o go to Mrs C. M o rr iso n f o r
h e r h e l p w i th h i s t o l o g i c a l method and to Dr D.G.
C ochrane and Mrs M. McCallum f o r i n s t r u c t i o n i n
e l e c t r o n m ic ro sco p e te c h n iq u e .
1 .
1. INTRODUCTION
Many a p h id s p e c i e s , w hich o c c u r as^ p a r th e n o g e n e t i c v iv i p a r o u s
morphs i n th e s p r i n g and summer, r e a c t to a d v e rse changes i n th e
e n v i ro n m e n t by p ro d u c in g a l a t e v i r g i n o p a r a e which f l y away and
c o l o n i s e new h o s t s . A sp e c ts o f th e en v iro n m en t which have been
shown to h e r a l d p o o r e n v i ro n m e n ta l c o n d i t i o n s arid to c a u se a l a t e
i n d i v i d u a l s to be p ro d u ced a r e changes i n te m p e ra tu r e ( Wadley, 1923;
Ewing, 1926; S h u l l , 1929; W hite 1946; K enten , 1955; Jo h n so n , 1 966a ;
Lamb & W h ite , 1966 ) and p h o to p e r io d ( S h u l l , 1928, 1929; W hite ,
1946; K i t z m i l l e r , 1950; K en ten , 1955; B u ck le , 1963a , b ( i n H i l l e R is
Lam bers, 19 6 6 ) ; M a c G i l l iv ra y & A nderson , 1964; Joh n so n , 1965? 1966b ) ,
c ro w d in g ( Wadley, 1923; R e in h a rd , 1927; Bonnemaison, 1949 > 1950>
1951; Noda, 1958; L ee s , 1961; Lowe & T a y lo r , 1964; Toba e t a l , 1967;
S u t h e r l a n d , 1969; Shaw, 1970a) and n u t r i t i o n ( S c h a e f e r , 1938;
W ilso n , 1938; Noda, 1956, 1958; Johnson & B i r k s , I9 6 0 ; Johnson ,
1 966b; B ranson & Sim pson, 1 9 6 6 ; S u th e r l a n d , 1967; L ees , 1966 ) .
The e f f e c t s o f n u t r i t i o n a r e u s u a l l y d i f f i c u l t to s e p a r a t e from th o s e
o f c ro w d in g s in c e a l a r g e p o p u la t io n o f a p h id s w i l l lo w e r the
q u a l i t y o f th e h o s t p l a n t .
C row ding a c t s a s a s t im u lu s i n v a r io u s ways and to d i f f e r e n t
d e g re e s i n d i f f e r e n t a p h id s p e c i e s . I n Megoura v i c i a e ( Buckton )
( L ees , 1961 ) and A c y r th o s ip h o n pisum ( H a r r i s ) ( S u th e r l a n d , 1969 )
c row d ing o f th e m o th e r o n ly i s im p o r ta n t w hereas i n A phis c r a c c iv o r a
( Koch ) ( J o h n so n , 1965 ) , Myzus p e r s i c a e ( Awram, 1968 ) , Aphis
2.
f a b a e ( Scop. ) ( Shaw, 1 9 7 0 a ) , C h a e to s ip h o n f r a g i f o l i a e ( C o c k e r e l l
( Judge &. S c h a e f e r s , 1971)> Macrosiphum g ran a r iu m (Woda, 1961) and
R hopalosiphum p a d i ( L. ) ( Dixon & G len , 1971 ) "both p r e - and
p o s t - n a t a l c row d ing i n f l u e n c e th e p r o p o r t i o n o f a l a t a e p roduced .
R hopalosiphum p r u n i f o l i a e ( Noda, 1958 ) and T h e r io a p h is m a c u la ta
( B uck ton ) ( Toba et_ a l , 1967 ) a r e r e s p o n s iv e to c row ding p u r e ly
p o s t - n a t a l l y and th e n o n ly d u r in g th e f i r s t e i g h t e e n h o u rs a f t e r
b i r t h .
The s i t u a t i o n so f a r s t u d i e d f o r B re v ic o ry n e b r a s s i c a e ( L.> )
i s v e ry c o n fu s e d . Bonnemaison ( 1951 ) found t h a t f o r a l a t a e to
be p ro d u c e d m o ther and o f f s p r i n g had to be r e a r e d t o g e t h e r ; i n
o t h e r w ords, some form o f m utual s t i m u l a t i o n o c c u r s . Kawada ( 1964 )
s u b s e q u e n t ly found t h a t when l a r v a e were r e a r e d i n crowds w i th o u t
t h e m o th e r from f i r s t i n s t a r to th e a d u l t s ta g e more became a l a t e
th a n when th e y were r e a r e d i n i s o l a t i o n , a l th o u g h q u a l i t y o f th e
h o s t p l a n t may have p la y e d a p a r t . Lamb and White ( 1966 ) ,
how ever, found t h a t B. b r a s s i c a e crowded f o r p e r io d s o f up to
tw en ty f o u r h o u rs p roduced no more a l a t e l a r v a e th a n th o s e r e a r e d
i n i s o l a t i o n .
o
Q u a l i t y o f th e fo o d p l a n t h a s been invoked a s a m a jo r cause
o f th e p r o d u c t io n o f a l a t e m orphs. S t a r v a t i o n was th o u g h t to be th e
r e a s o n f o r i n c r e a s e d numbers o f a l a t a e i n A. pisum ( S c h a e fe r , 1938 )
P i n t e r a ( 1957 ) w ork ing w i th M. p e r s i c a e and Johnson ( 1966a ) w i th
A. c r a c c i v o r a came to s i m i l a r c o n c lu s io n s . However, th e most
3. im p o r ta n t n u t r i t i o n a l f a c t o r , f i r s t s u g g e s te d by Evans ( 1938 )
w ork in g on B. b r a s s i c a e , seems to be v a r i a t i o n in th e amount o f
a m in o - n i t r o g e n . When young D ysaph is d e v e c ta were r e a r e d on p l a n t s
g iv e n a n i t r o g e n d e f i c i e n t d i e t f o r th e f i r s t f o u r days o f l i f e a
l a r g e p r o p o r t i o n became a l a t e ( F o r r e s t , 1970 ) . M ature p l a n t t i s s u e
c o n t a i n s l e s s a m in o -n i t ro g e n th a n young o r s e n e s c in g t i s s u e and i t
i s on m a tu re t i s s u e t h a t h ig h e r numbers o f a l a t a e te n d to be
p ro d u ced ( P i n t e r a , 1957; Jo h n so n , 1966b ; S u th e r l a n d , 1969 )•
L a b o r a to r y s t u d i e s in v o l v in g r e a r i n g Myzus p e r s i c a e on s y n t h e t i c
d i e t s a p p e a r to c o n t r a d i c t th e r e s u l t s o b ta in e d u s in g whole p l a p t
d i e t s . D e f i c i e n c i e s i n amino a c i d s and s u c ro s e i n th e m a te rn a l d i e t
gave r i s e to a g r e a t e r p r o p o r t i o n o f a p t e r a e amongst th e o f f s p r i n g
( M i t t l e r & K l e i n j a n , 1970 ) . A r t i f i c i a l d i e t s , how ever, may l a c k
s u b s t a n c e s e s s e n t i a l f o r a l a t a p r o d u c t io n which o c c u r i n whole
p l a n t s b u t which have n o t y e t been i d e n t i f i e d . R. p a d i r e a r e d i n
i s o l a t i o n on m a tu r in g b i r d c h e r r y p roduced s m a l l e r o f f s p r i n g in
s u c c e s s i v e g e n e r a t i o n s ( Dixon & G len, 1971 )•
A l a t a p r o d u c t i o n i s in d u c e d in many s p e c i e s by low te m p e r a tu r e s
( W hite , 1946; Noda, 1954; Johnson & B i r k s , I960 ; Lamb & W hite , 1 9 6 6 ;
L e e s , 1967 )• O f te n th e e f f e c t o f t e m p e ra tu re i s i n t e r r e l a t e d w ith
some o t h e r f a c t o r e . g . n a t u r e o f th e h o s t ( Noda, 1954 ) a s i n
R. p r u n i f o l i a e , p h o to p e r io d a s i n A. c r a o c iv o r a ( Jo h n so n , 1965 )•
B oth p h o to p e r io d and te m p e ra tu re can a f f e c t th e t h r e s h o l d o f re s p o n se
to o t h e r s t i m u l i ( Jo h n so n , 1966a ) .
A la ta e have been d e s c r ib e d a s o b l i g a t o r y m ig ra n ts d i f f e r i n g
p h y s i o l o g i c a l l y and b e h a v i o u r a l l y a s w e l l a s s t r u c t u r a l l y from th e
a p t e r o u s morph o f th e same s p e c i e s . Some m ig ra to ry i n s e c t s p e c ie s
p ro d u c e w inged i n t e r f o r m s , which do n o t have com ple te w ings o r
w ing m u sc le s . Aphid s p e c i e s p roduce th e s e i n t e r m e d i a t e s which
r a n g e from a p t e r o u s i n d i v i d u a l s w ith a l a t a - l i k e s c l e r o t i s a t i o n o f
th e t h o r a x and abdomen to a l a t a e w i th one wing s h o r t e r th a n a n o th e r
o r w i th m i n ia t u r e w ings ( L ees , 1966 ) .
I n many i n s e c t s m ig r a t io n o c c u rs i n young i n d i v i d u a l s b e f o r e
th e o v a r i e s a r e m a tu re . T h is c o n n e c t io n betw een m ig r a to r y b e h a v io u r
and p r e - o v i p o s i t i o n s t a g e s was f i r s t p o in t e d o u t a s a r e s u l t o f
work on. l o c u s t s and a p h id s ( Kennedy, 1956, 1961; Jo h n so n , 1963 ) .
I t h a s been s u g g e s te d t h a t i n m ig ra to ry i n d i v i d u a l s s e n s o r i - m o to r
f u n c t i o n s a r e d e v e lo p e d a t th e expense o f v e g e t a t i v e f u n c t i o n s i . e .
s e t t l i n g , f e e d i n g and l a r v i p o s i t i o n ( Kennedy, 195&J 1961 ) . T h is
a n t a g o n i s t i c developm ent o f s e n s o r i - m o to r and v e g e t a t i v e f u n c t i o n s
h a s been c a l l e d th e " o o g e n e s i s - f l i g h t syndrome" ( Jo h n so n , 1963* 1969 )*
E n v iro n m e n ta l c o n d i t i o n s a r e th o u g h t to a c t on an a p h id d u r in g
i t s developm ent f a v o u r in g one o r o t h e r o f two a n t a g o n i s t i c sy s tem s , c
t h e f i r s t p ro m o tin g m ig r a t i o n by th e developm ent o f f l i g h t m u sc les
and th e b u i l d - u p o f f a t and g ly c o g en r e s e r v e s and th e second
p ro m o t in g th e v e g e t a t i v e f u n c t i o n s o f s e t t l i n g , f e e d in g and
l a r v i p o s i t i o n ( Kennedy, 1961 ) . When an i n s e c t becomes a d u l t i t s
s t r u c t u r a l developm ent h as a l r e a d y d e te rm in e d w h e th e r i t w i l l
m i g r a t e o r n o t . I t h a s been s u g g e s te d , how ever, t h a t th e o o g e n e s i s -
f l i g h t syndrome i s more a m easure o f th e a p h i d ’ s a b i l i t y to f l y
when g r a v i d th a n a m easure o f m ig r a to r y c a p a c i t y ( D ixon, 1971 )•
I t was s u g g e s te d t h a t a polym orphism o f b e h a v io u r and
p h y s io lo g y a s w e l l a s o f s t r u c t u r e m igh t o c c u r i n a p h id s ( Johnson ,
1963 ) . R ecen t work on A. fa b a e h a s g iv e n more w e ig h t to th e
o n t o g e n e t i c th e o ry o f f l i g h t b e h a v io u r . D i f f e r e n t d e g re e s o f e x p r e s s io n
o f m i g r a to r y u rg e a r e seen among a l a t a e o f A. f a b a e . I n a youn^
c o lo n y l a r g e a l a t a e a r e p ro d u ced . These a re m a in ly " f l i e r s " which
d e p o s i t some l a r v a e b e f o r e th e y f l y and " n o n - f l i e r s " which n e v e r f l y .
However, no a t te m p t was made to make " n o n - f l i e r s " f l y . As th e co lo n y
grow s th e a l a t a e p ro d u ced become s m a l l e r , have a s l i g h t e r wing
l o a d i n g and f l y w i th o u t d e p o s i t i n g l a r v a e . These " m ig ra n ts "
d im in i s h i n numbers a s th e co lo n y n e a r s th e end o f i t s l i f e and
" f l i e r s " and " n o n - f l i e r s " a g a in p redom ina te ( Shaw, 1970b, c ) .
The o n to g e n e t i c th e o ry a l lo w s no b e h a v io u r a l c h o ic e f o r an
a p h id w hich i s a l a t e because o f c o n d i t i o n s e x p e r i e n c e d by i t s
m o th e r o r td u r in g i t s e a r l y l i f e , and which su d d en ly f i n d s i t s e l f
i n a f a v o u r a b le e n v iro n m e n t . A s i t u a t i o n where an a l a t a spends i t s
l a r v a l l i f e i n a f a v o u r a b l e env ironm en t which l a t e r becomes
u n f a v o u r a b le must a l s o f r e q u e n t l y a r i s e . In s p e c i e s where a l a t e
c h a r a c t e r s a re i n f l u e n c e d by c o n d i t i o n s d u r in g l a r v a l l i f e
i n t e r m e d i a t e s , which canno t f l y , w i l l a r i s e a s i n A. fa b a e ( Shaw,
1 9 7 0 c ) . However, i n s p e c i e s where a l a t a d e t e r m in a t io n o c c u rs
6 .
b e f o r e b i r t h , th e s i t u a t i o n i s v e ry d i f f e r e n t b e c a u se a l l a l a t a e
w i l l be s t r u c t u r a l l y c a p a b le o f f l i g h t when th e y m oult to a d u l t .
Any b e h a v i o u r a l i n t e r m e d ia c y c o u ld n o t be a s s o c i a t e d w ith d i f f e r e n c e s
i n w ing lo a d in g , amount o f w ing m uscle o r th e q u a n t i t y o f f u e l
s t o r e d a s f a t .
To t e s t w h e th e r an o n to g e n e t i c th e o ry can e x p l a i n th e f l i g h t
b e h a v io u r o f a p h id s th e v e t c h a p h id , Megoura v i c i a e ( Buckton )
was u s e d . I n t h i s a p h id a l a t a d e t e r m in a t io n o c c u r s b e f o r e b i r t h
( L e e s , 1967 ) .
r r ; : o r ' . ' r . r ; s r . . " 3 r r r r ; - :• ' -xxxx
-. i/r f .0 . r r y r r r,-
u tixrj-Xix V. r •... r r
• ; : :: „ '-xx " -x '> „
. x x x 1 r ; c f ' yx r x v .\ ,- r 1 r. ’ 'ir
iiJA j r r i . t v : i r ' : r f r i r ?
7 .
2. MATERIALS AND METHODS.
A p a r th e n o g e n e t i c c lo n e o f Megoura v i c i a e , b ro u g h t from
R o th a m s ted E x p e r im e n ta l S t a t i o n in 1968, was m a in ta in e d a s a
p a r t h e n o g e n e t i c c lo n e f o r u se i n th e e x p e r im e n ts d e s c r ib e d h e r e .
The a p h id s were r e a r e d on s e e d l i n g s o f b ro a d b ean , V ic i a f a b a
( L. ) v a r . K e r r ' s E x h i b i t i o n Longpod. Beans were soaked f o r 24
h o u r s and th e n p la c e d be tw een l a y e r s o f damp c o t t o n wool to
g e r m i n a te . F iv e o r s i x days l a t e r , when th e s e e d l i n g s were a t th e
"hook s t a g e " , th e y were p l a n t e d i n John In n e s No. 1 P o t t i n g Compost
i n 4if" p l a n t p o t s . About e i g h t days a f t e r g e rm in a t io n th e s e e d l i n g s
w ere r e a d y f o r u se a s h o s t p l a n t s .
A ph ids were r e a r e d i n d o o r s u n d e r c o n s t a n t c o n d i t i o n s . A d a i l y
reg im e o f 17 h o u r s l i g h t and 7 h o u rs d a rk n e s s w i th t e m p e r a tu r e s o f o o .
20 C d u r in g th e l i g h t p e r io d and 15 C d u r in g th e d a rk p e r io d , g iv i n g o
a d a i l y a v e ra g e o f 1 8 .5 C, was m a in ta in e d th ro u g h o u t a l l e x p e r im e n ts .
The w a l l s and c e i l i n g o f th e room were l i n e d w ith r e f l e c t i n g
f o i l . 80 W att d a y l i g h t and w h ite f l u o r e s c e n t l i g h t s gave a l i g h t
i n t e n s i t y o f 3660 m e tre c a n d le s ( 340 f o o t c a n d le s ) a t bench l e v e l .
R e l a t i v e h u m id i ty rem a in ed a t a p p r ix im a te ly 70$.
8
H a n d l in g a p h i d s .
F i r s t and seco n d i n s t a r l a r v a e were t r a n s f e r r e d from one
p l a n t to a n o t h e r by means o f a camel h a i r b ru s h . O ld e r l a r v a e and
a d u l t s were removed from one h o s t by s h a k in g o r t a p p in g th e p l a n t
so t h a t th e y would f a l l i n t o a specim en tu b e . These were a l lo w ed
to c raw l on t o a new h o s t w i th o u t i n t e r f e r e n c e from th e e x p e r im e n te r .
T h is l a t t e r method i s th o u g h t to be u n l i k e l y to i n t e r f e r e w i th th e
s u b s e q u e n t b e h a v io u r <5f th e a n im a ls s in c e th e av o id an ce b e h a v io u r
and s t r u g g l i n g , w hich u s u a l l y a r i s e when th e l a r g e r l a r v a e and
a d u l t s a r e p ic k e d up w i th a camel h a i r b r u s h , do n o t o c c u r .
P r o d u c t i o n o f a l a t a e .
To o b t a i n r e g u l a r q u a n t i t i e s o f a l a t e v i r g i n o p a r a e a d u l t
a p t e r a e were crowded u s in g L e e s ' ( 1961 ) method. 10 a p t e r a e were
crow ded f o r 24 h o u r s i n a 2 .5 x 5 cm specim en tu b e c o n t a i n i n g a
p i e c e o f m o is t f i l t e r p a p e r . A f te rw a rd s th e y were r e t u r n e d s i n g l y
t o b ean s e e d l i n g s t o r e p ro d u c e . A la ta e were th e n p ro d u ced .
F l i g h t c a b i n e t .
When a l a t a e m o u lted to a d u l t th e h o s t p l a n t s w i th th e a p h id s
w ere p la c e d i n th e b l a c k p a i n t e d chamber o f th e f l i g h t c a b i n e t
F ig u r e 1 . F l i g h t c a b i n e t (D ix o n , 1 9 6 9 ) .
Black White Fluorescent light cham ber chamber cham ber
9 .
shown i n F ig u re 1 ( D ixon, 1969 )•
A la t a e t a k i n g o f f from th e p l a n t a r e a t t r a c t e d "by th e f l u o r e s c e n t
l i g h t s and f l y to w a rd s th e s l o p i n g s h e e t s o f g l a s s ( a i n F ig u re 1 ) .
They a l i g h t on th e g l a s s , c raw l to w ard s th e gap "between th e p l a t e s
and e i t h e r f l y o r c raw l i n t o th e w h ite m idd le cham ber. Once i n s i d e
th e m idd le cham ber th e y do n o t r e t u r n to th e h o s t p l a n t . By means
o f sm a l l d o o rs a t e i t h e r end o f th e w h i te chamber th e flow n a p h id s
can be removed from th e s h e e t o f g l a s s ( b ) f a c i n g th e l i g h t s o r
from th e c e i l i n g o r f l o o r o f th e w h ite chamber.
When s e t t l i n g a f t e r f l i g h t i s r e q u i r e d to ta k e p la c e w i th o u t
i n t e r f e r e n c e from th e e x p e r im e n te r p l a n t s can be p la c e d in th e
w h i te cham ber and removed when an a p h id h a s a l i g h t e d and begun to
f e e d .
O v e r h e a t in g o f th e f l i g h t c a b i n e t i s p r e v e n te d by c i r c u l a t i n g
a i r th ro u g h th e f l u o r e s c e n t . l i g h t chamber by means o f a fa n in th e
to p and a i r v e n t s i n th e bo tto m o f th e l i g h t cham ber.
P l a n t p o t s a r e p la c e d i n a t r a y o f w a te r i n th e b l a c k chamber
so t h a t any a p h id c r a w l i n g o r f a l l i n g from i t s p l a n t ca n n o t re a c h
th e m idd le cham ber. Any a l a t e a p h id found i n th e m idd le chamber
h a s t h e r e f o r e f low n .
F l i e r s and n o n - f l i e r s .
I f an a l a t a t a k e s o f f from th e h o s t p l a n t i t i s a f l i e r , i f
i t r e m a in s on th e p l a n t i t i s a n o n - f l i e r .
L i g h t m ic ro sco p e s t u d i e s .
L egs , a n te n n a e and w ings were removed from a l a t e a p h id s
b e f o r e f i x a t i o n i n B o u in 's F i x a t i v e . The spec im ens were embedded
i n e s t e r wax and c u t e i t h e r i n l o n g i t u d i n a l o r i n s a g i t t a l s e c t i o n s
o f 6 p. t h i c k n e s s . They were a r r a n g e d s e r i a l l y on s l i d e s , s t a i n e d
i n M ayer1s-Haemalum and E o s in and mounted i n Canada Balsam.
E l e c t r o n m ic ro sco p e s t u d i e s .
Whole t h o r a c e s o f a l a t e a p h id s , w i th w ings and l e g s removed,
w ere f i x e d u s i n g a doub le f i x a t i o n method w i th g lu t a r a ld e h y d e and
osmium t e t r o x i d e i n a p h o sp h a te b u f f e r , pH 6 .8 .
I n o r d e r t o l o c a t e and o r i e n t a t e th e m uscle c o r r e c t l y t h i c k
s e c t i o n s ( a b o u t 1 p ) were ta k e n on th e LKB u l t r a m ic ro to m e and
s t a i n e d w i th 1$ Azur 11_ - M ethy lene b lu e ( R ic h a rd so n , J a r r e t &
F in k e , 1960 ) .
500X - 600A s e c t i o n s were c u t on th e u l t r a to m e , s t a i n e d w ith
u r a n y l a c e t a t e and l e a d c i t r a t e and v iew ed on an AEI EM6 E l e c t r o n
F ig u r e 2. C a p i l l a r y R e s p i r o m e te r ( a f t e r D ixon (1970 ) )•
I 1 I I I 11 I I I I I I I I <
m anom eter
fil ter p a p e r w e t t e d
w ith KOH
cot ton w oo l p lug
f i l t e r p a p e r
p la t fo rm
flask
M ic ro s c o p e , C r o s s - s e c t i o n a l a r e a s o f m i to c h o n d r ia and m uscle
f i b r i l s were m easu red u s in g a p l a n im e t e r on th e r e s u l t i n g m ic ro g rap h
R e s p i r o m e t r y .
R e s p i r a t i o n r a t e s o f a p h id s were m easured u s i n g th e c a p i l l a r y
r e s p i r o m e t e r ( Engelmann, 19^3 ) . T h is c o n s i s t s o f a manometer
made w i th p r e c i s i o n h o re g l a s s t u b i n g o f . 5 mm d ia m e te r and a sm a l l
f l a s k w i th a volume o f . 5 ml ( F ig u re 2 ) i n which th e a p h id i s
p la c e d * A sm all p i e c e o f f i l t e r p a p e r i s u se d to l i n e th e f l a s k
so t h a t th e a p h id h a s a rough s u r f a c e to g r i p and w i l l n o t spend i t s
t im e s t r u g g l i n g .
A number o f such f l a s k s and m anometers a r e c o n n e c te d to a
l a r g e b o t t l e o f a i r and th e whole a p p a r a tu s i s k e p t a t th e r e q u i r e d
t e m p e r a t u r e by im m ers ing i t i n a w a te r b a t h . R ead ings a r e made
d i r e c t l y from a s c a l e b e h in d each manometer. The p ie c e o f f i l t e r
p a p e r i n th e cham ber a t th e end o f th e manometer tu b e i s soaked
w i th c o n c e n t r a t e d KOH s o l u t i o n to a b so rb C02 when 0^ up take , i s
b e i n g m easured .
12* RESULTS
3 (a )* FLIGHT BEHAVIOUR
I n an e a r l i e r e x p e r im e n t i t was found t h a t a l a t a e o f M. v i c i a e
can r e s p o n d to c u r r e n t a d v e r s e c o n d i t i o n s . When crowded w ith o th e r
a p h id s from th e f o u r t h i n s t a r a much h i g h e r p r o p o r t i o n o f a l a t a e
f le w on r e a c h i n g th e a d u l t s t a g e th a n when a l a t a e were i s o l a t e d
from t h i s t im e ( D ixon, B urns & Wanghoonkong, 1968 ) .
F u r t h e r e x p e r im e n t s i n v e s t i g a t i n g th e f l i g h t r e s p o n s e o f
a l a t a e o f M. v i c i a e to d i f f e r e n t c o n d i t i o n s d u r in g l a r v a l developm ent
and a t th e t im e o f a d u l t m ou lt a r e d e s c r ib e d h e r e .
T e m p e ra tu re , h u m id i ty and p h o to p e r io d rem a ined c o n s t a n t
th ro u g h o u t th e e x p e r im e n ts ( p . 7 )• N u t r i t i o n does n o t a f f e c t a l a t a
p r o d u c t i o n in M. v i c i a e ( L ees , 19&7 ) an<i so onl y d i f f e r e n c e s
w hich c o u ld a r i s e be tw een i n d i v i d u a l a l a t a e , a p a r t from a random
v a r i a t i o n , would be th e r e s u l t o f e x p e r ie n c e o f p r e v io u s g e n e r a t i o n s .
The b e s t c u m u la t iv e m easure o f t h i s was th o u g h t to be th e p e rc e n ta g e
o f a l a t a e among th e o f f s p r i n g o f th e m o the rs o f th e e x p e r im e n ta l
a l a t a e . As l a r v a e were i s o l a t e d d u r in g th e f i r s t one to t h r e e
d ays a f t e r th e c ro w d in g t r e a tm e n t th e c o n d i t i o n s e x p e r ie n c e d by
th e m o th e r were u n l i k e l y to have v a r i e d s u f f i c i e n t l y f o r any
g r e a t v a r i a t i o n to have been im p a r te d to h e r o f f s p r i n g i n t h i s
t im e .
Table 1. Numbers of alatae flying and remaining on the plant when isolated alatae are crowded at ij.th instar and just after the adult moult.
REARING- CONDITIONS ' PLIERS NON-PLIERS
Crowded after moult with 30 3rd instars
10
t2
TOTAL
6
12
1 3 .
A p te ro u s v i r g i n o p a r a e which had "been r e a r e d i n i s o l a t i o n
from " b ir th were g iv e n th e s t a n d a r d crow ding t r e a tm e n t ( p . 8 )
and th e l a r v a e s u b s e q u e n t ly p ro d u ced r e a r e d i n i s o l a t i o n o r in
crow ds on young bean s e e d l i n g s . When a l a t a e were crowded a f t e r
a d u l t m o u lt o r d u r i n g th e f o u r t h i n s t a r th e same p r o p o r t i o n f lew
( T ab le 1 ) . S in c e c row d ing a f t e r a d u l t m oult had to be done
w i th i n 12 h o u rs o f th e moultt c row ding a t f o u r t h i n s t a r was more
c o n v e n ie n t and was u se d in a l l s u b se q u e n t e x p e r im e n ts .
F o u r r e a r i n g re g im e s were u sed :
( i ) i s o l a t i o n from b i r t h u n t i l t im e o f f l i g h t
( i i ) i s o l a t i o n u n t i l f o u r t h i n s t a r , th e n crowded on th e
o r i g i n a l p l a n t w i th a number o f t h i r d i n s t a r nymphs
( i i i ) crow ded r e a r i n g from day o f b i r t h u n t i l t im e o f f l i g h t
( i v ) crow ded r e a r i n g u n t i l th e f o u r t h i n s t a r , th e n
i s o l a t i o n on f r e s h s e e d l i n g s .
R e s u l t s o f th e e x p e r im e n ts a r e g iv e n i n T a b le s 1 to 4 in
A ppendix 1 and i n F ig u r e s 3 to 7*
The r e l a t i o n s h i p s be tw een p e rc e n ta g e f l i e r s (Y) and th e
p e r c e n ta g e a l a t e o f f s p r i n g o f th e m o th e r (X^) and th e s i z e o f
crowd (X^) fo r . th e f o u r r e a r i n g c o n d i t i o n s a r e r e p r e s e n t e d by
e q u a t io n s 1 to 5 below .
F ig u r e 3. P e r c e n t a g e f l i e r s a r i s i n g when a l a t a e a r e
i s o l a t e d from b i r t h u n t i l t im e o f f l i g h t p l o t t e d c
a g a i n s t th e p e r c e n ta g e a l a t e p ro g en y o f th e m o th e r .
50- O
% flie rs
o 10 20 30 40 50 60
% a la te progeny of m other
F ig u r e 4 . P e r c e n t a g e f l i e r s a r i s i n g when a l a t a e a r e
r e a r e d i n crow ds u n t i l t h e f o u r t h i n s t a r and c
t h e n i s o l a t e d a g a i n s t p e r c e n t a g e a l a t e p rog en y
o f t h e m o th e r .
70n
“ I-------------- \— o 1-------------- 1— 10 20 30 40
% a la te p ro g en y of m o th e r
—i 50
F ig u r e 5* P e r c e n t a g e f l i e r s a r i s i n g when a l a t a e a r e
cr.owded u n t i l t h e f o u r t h i n s t a r and th e n i s o l a t e d
a g a i n s t t h e s i z e o f crowd i n w hich th e y w ere
r e a r e d .
60
50
40 -
% fliers
30
20
10
“ I— 80
14 .
( 1 ) Y = 3 3 . 6 4 0 - 0 . 0 4 5 X } ( i )
f o r co m parison w i th z e ro s lo p e , t = 0 .2 1 6 3 ,
d . f . = 13* n o t s i g n i f i c a n t .
(2 ) Y = 5 .4 9 8 + 0.107X + 0.383X2 ( i i )
f o r co m p ar iso n w i th z e ro s lo p e , t(X ^ ) = 0.351*
d . f . = 5, n o t s i g n i f i c a n t ; t (X 2 ) = 2.373*
d . f . = 5, P < 0 .1 0 .
(3 ) Y - 4 .3 2 8 + 0.355X1 + 0 . 505X2 ( i i i )
f o r com p ariso n w i th z e ro s lo p e , t (X n ) = 1.659*X y d . f . = 1 5 * n o t s i g n i f i c a n t ; t (X 2 ) = 2 . 9 7 1 *
d . f . « 15 , P < 0 .0 1 .
(4 ) Y = 2 9 .6 8 6 + 0.392X1 ( i v )
f o r co m p ar iso n w i th z e ro s lo p e , t = 0 , 9 9 1 *
d s f . = 12, n o t s i g n i f i c a n t .
( 5 ) Y = 4 4 .2 1 3 + O.O7 IX2 ( i v )
f o r co m p ar iso n w i th ze ro s lo p e , t = 0.444*
d . f . = 1 2 , n o t s i g n i f i c a n t .
The s i t u a t i o n where a l a t a e were crowded to f o u r t h i n s t a r
and th e n i s o l a t e d ( i v ) i s d e s c r ib e d by e q u a t io n s 4 and 5 above.
A n a ly s i s o f th e t h r e e f a c t o r s in v o lv e d , p e rc e n ta g e f l i e r s (Y ),
s i z e o f crowd (X2 ) and th e p e r c e n ta g e a l a t e p rogeny o f th e m other
(X ^) , by means o f a m u l t i p l e r e g r e s s i o n c a l c u l a t i o n s i m i l a r to
t h a t u s e d f o r _ii and i i i i n d i c a t e d t h a t t h e r e was no s i g n i f i c a n t
c o r r e l a t i o n betw een Y and Xx and Y and X2» Each v a r i a b l e (X) was
F ig u r e 6. The r e l a t i o n s h i p b e tw ee n p e r c e n t a g e f l i e r s and
p e r c e n t a g e a l a t e p ro g e n y o f th e m o th e r and th e s i z e
o f crowd when a l a t a e a r e crow ded from f i r s t i n s t a r
u n t i l t h e t im e o f f l i g h t .
100
80
60
40
20
X a la te p rogeny of m other2020
0
F ig u r e 7« The r e l a t i o n s h i p "between p e r c e n ta g e f l i e r s and
t h e p e r c e n ta g e a l a t e o f f s p r i n g o f th e m o th e r and
th e s i z e o f crowd when a l a t a e a r e i s o l a t e d from
f i r s t t o f o u r t h i n s t a r and th e n crowded.
% fliers
100
80
60
40
20
progeny of m other
0
15 .
r e c a l c u l a t e d u s i n g a s im p le r e g r e s s i o n a n a l y s i s .
When a l a t a e a r e i s o l a t e d from f o u r t h i n s t a r , no m a t t e r
w h e th e r th e y have "been i n i s o l a t i o n o r i n crowds b e f o r e t h i s ,
a h ig h p r o p r t i o n o f them rem ain on th e p l a n t . The mean p e r c e n ta g e
o f a p h id s t h a t f l y i s 32 . 1$ ( 95$ c o n f id e n c e l i m i t s 3 0 .1 $ and
3 3 .9 $ ) when a l a t a e a r e i s o l a t e d from day o f b i r t h and 4 1 . 4$
( 95$ c o n f id e n c e l i m i t s 38 . 6$ and 44-2$ ) when th e y a r e i s o l a t e d
a f t e r th e f o u r t h i n s t a r ( T a b le s 1 and 2 i n A ppendix 1, F ig u r e s
3 and 4 )• When th e y a r e crowded a t tim e o f a d u l t m oult p r e v io u s
i s o l a t i o n doe's n o t s i g n i f i c a n t l y a f f e c t th e numbers f l y i n g
( e q u a t io n 2, F ig u re 6, T ab le 3 i n Appendix 1 ) , a l th o u g h few er
f l y th a n when th e y have been crowded from b i r t h ( e q u a t io n 3>
F ig u re 7> T ab le 4 i n A ppendix 1 ) . I n b o th c a s e s where a l a t a e
were r e a r e d from b i r t h i n crowds th e p e rc e n ta g e o f a p h id s f l y i n g
i s h i g h e r ( i i i and i v ) th a n i n s i t u a t i o n s where th e a l a t a e were
i s o l a t e d from b i r t h ( i and i i ) ( F ig u re 8 ) . L a rv a l e x p e r ie n c e
th u s i n f l u e n c e s th e number o f a l a t a e f l y i n g b u t t h i s f a c t o r i s
o u tw e ig h ed by th e e f f e c t o f c u r r e n t c o n d i t i o n s on t h e i r b e h a v io u r .
T here i s no s i g n i f i c a n t r e l a t i o n s h i p be tw een p e r c e n ta g e o f
a l a t a e f l y i n g and th e p e rc e n ta g e a l a t e progeny o f th e m other i n any
o f th e s i t u a t i o n s d e s c r ib e d above ( F ig u r e s 3» 4» 6 and 7 )•
However, when a l a t a e a r e crowded from b i r t h to th e a d u l t moult
th e c o e f f i c i e n t o f th e p a r t i a l r e g r e s s i o n o f p e rc e n ta g e f l i e r s
(T) on th e p e r c e n ta g e a l a t e p ro g en y o f th e m other (X^ ) i s
F ig u r e 8 . A s i m p l i f i e d r e p r e s e n t a t i o n o f th e p e rc e n ta g e
o f a l a t a e f l y i n g when r e a r e d u n d e r d i f f e r e n t re g im e s
o f c row ding and i s o l a t i o n .
- : * ifl i ers
100
80
60
40
20
iso la te crowd to isolate to crowd 1st ins tar 4 th ins tar 4 th in s t a r 1st in s t a r to flight th e n iso la te th en crowd to f l ight
16 .
s i g n i f i c a n t l y d i f f e r e n t from z e ro a t th e 20$ l e v e l ( e q u a t io n 3,
F ig u re 7 )• T h i s s u g g e s t s t h a t m a te rn a l e x p e r i e n c e may a f f e c t
numbers f l y i n g i n th e f o l l o w i n g g e n e r a t i o n .
To d e te rm in e w h e th e r t h e r e i s any c u m u la t iv e g e n e r a t i o n
e f f e c t on f l i g h t one c lo n e o f a p t e r a e was r e a r e d in i s o l a t i o n f o r
e i g h t g e n e r a t i o n s and a second r e a r e d i n crowds o f 30 f o r s i x
g e n e r a t i o n s . Both c lo n e s o r i g i n a t e d from th e same a p t e r o u s d a u g h te r
o f an a l a t a . -Each g e n e r a t i o n was m o n i to re d f o r r e s p o n s e to c row ding
by t a k i n g a d u l t a p t e r a e , s i b l i n g s o f th o s e d e s t i n e d to be m o the rs
o f th e n e x t g e n e r a t i o n , c row d ing them t e n a t a tim e f o r 24 h o u rs
i n a specim en tu b e , r e t u r n i n g them to s e e d l i n g s and s u b j e c t i n g
th e r e s u l t i n g o f f s p r i n g from day o f b i r t h to e i t h e r i s o l a t i o n o r
c ro w d in g , 30 on one p l a n t . The r e s u l t s a r e shown i n T ab le 2.
Where a l a t a e were i s o l a t e d numbers a r e low. Large b a t c h e s o f
l a r v a e had to be i s o l a t e d from each c lo n e a t th e same tim e in
o r d e r to o b t a i n r e a s o n a b le numbers o f a l a t a e and th e bench space -<
a v a i l a b l e l i m i t e d th e number o f p l a n t s t h a t c o u ld be u s e d a t one
t im e .
J u s t a f t e r th e a l a t a e from g e n e r a t io n 2 were p u t i n th e
f l i g h t c a b i n e t a f a u l t i n th e te m p e ra tu r e r e g u l a t i o n system
o c c u r r e d and t h e r e was a sudden d r a s t i c f a l l i n te m p e ra tu r e from
Table 2, Numbers and percentages of alatae produced in successive generations by a clone of isolated and a
clone of crowded apterae and the percentages of their alate offspring which fly as adults when subjected to different regimes of crowding and isolation.
ISOLATED CROWDED Generation ^alatae No. alatae % fliers No. alatae ¥ fli Isolated
1 clone
12.3 0 0 9 55.6 2 3.2 1 100 0 0 3 . 1U.6 2 0 5 100 b U2.9 5 29 13 61.5 5 39.1 9 37.5 - -
. 6 2 9 .b 10 10 15 53.3 8 1 5 .6 § b o 9 100
Crowded 1
clone 2 7 .6 b 50 12 75
3 30.5 b 25 21 85.7 k c 2 9 .2 - - 7 71. b 6 2 9 .2 3 0 16 93.8
O o 20 C to 10 C w i t h i n a few h o u r s . The e f f e c t o f t h i s was to
p ro d u ce an i n c r e a s e i n num bers , o f b o th i s o l a t e d and crowded
a l a t a e , t a k i n g o f f . G e n e ra t io n 2 o f th e crowded c lo n e i s t h e r e f o r e
n o t i n c lu d e d i n T a b le 2.
I n th e crowded c lo n e th e p e r c e n ta g e o f a l a t a e p ro d u ced
d id n o t change a p p r e c i a b l y o v e r s i x g e n e r a t i o n s . T h is was c o n t r a r y
t o th e r e s u l t s o b t a in e d w i th th e i s o l a t e d c lo n e which f l u c t u a t e d
w i l d l y from g e n e r a t i o n to g e n e r a t i o n ( T ab le 2 ) . 0
T here i s no c u m u la t iv e e f f e c t o f i s o l a t i o n o r c ro w d in g o f th e
m o th e rs on th e p e r c e n ta g e o f o f f s p r i n g f l y i n g when a l a t a e a re
crowded o r i s o l a t e d from b i r t h . The l e n g t h o f t im e ( 3 months )
ta k e n f o r t h i s e x p e r im e n t and th e f a c t t h a t a l l a v a i l a b l e space
had to be u s e d p r e v e n t e d a r e p e a t o f th e work.
3 ( b ) . ACTIVITY OF APTERAE
O b s e r v a t io n s o f th e a c t i v i t y o f a p t e r a e on p l a n t s showed
t h a t when th e y were crowded th e y became more r e s t l e s s and l e f t th e
p l a n t more r e a d i l y . On s i n g l e p l a n t s w i th s i n g l e g row ing p o i n t s
t h e r e i s a n e g a t i v e c o r r e l a t i o n be tw een th e s i z e o f crowd on th e
p l a n t and th e l e n g t h o f tim e an a d u l t a p t e r a from t h a t c o lo n y w i l l
rem a in on th e p l a n t ( T ab le 3 )• A p te ra e were marked w i th s p o t s
o f n o n - t o x i c enamel p a i n t on th e d o r s a l s u r f a c e o f th e abdomen.
In c o l o n i e s o f 60 a p h id s and more th e te n d en cy was f o r p r e v i o u s l y
i s o l a t e d a p t e r a e to move a round th e m idd le o f th e p l a n t and
downwards b u t i n s m a l l e r crowds th e a p t e r a e moved up to w a rd s th e
g row ing p o i n t and s t a y e d t h e r e ( T ab le 3 )• Newly m o u l ted a p t e r a e
i n a l a r g e co lo n y c o n s i s t i n g o f t h i r d and f o u r t h i n s t a r s were seen
to w ander ab o u t on th e p l a n t . W ith in two days a l l t h e f o u r t h
i n s t a r l a r v a e had m o u lted to a d u l t and a l l b u t t h r e e had l e f t th e
p l a n t . A p te ra e r e a r e d i n crowds s e t t l e d down when i s o l a t e d on
s e e d l i n g s b u t w andered o f f ' t h e p l a n t w i th i n a few days when p la c e d
on h e a v i l y i n f e s t e d p l a n t s .
A p te ra e p la c e d s i n g l y on p l a n t s w i th more th a n one g row ing
p o i n t moved up and down th e s h o o ts re m a in in g f o r a few days a t each
g row ing p o i n t where th e y d e p o s i t e d l a r v a e . The p l a n t s were c o v e re d
s y s t e m a t i c a l l y by movements up th e s h o o ts to th e t i p s f o l lo w e d
by downward movements u n t i l a sh o o t o r l e a f which was g row ing
upward was e n c o u n te r e d . In t h i s way most o f th e p l a n t was c o v e re d
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before, on one l a s t downward e x c u r s io n , th e a p h id l e f t ;the p l a n t .
A p te ra e and a l a t a e behave s i m i l a r l y i n i s o l a t e d and crowded
c o n d i t i o n s . I s o l a t i o n p ro m o tes s e t t l i n g , f e e d i n g and r e p r o d u c t io n
w h i le c ro w d in g c a u s e s movement o v e r th e p l a n t and e v e n tu a l m i g r a t i o n
e i t h e r by f l i g h t o r by w a lk in g .
3 ( c ) . BEHAVIOUR OF INDIVIDUAL ALATAE
BEFORE FLIGHT
One day a f t e r a d u l t m ou lt f l i e r s become v e ry a c t i v e and wander
o v e r th e p l a n t ( F ig u r e 9a ) u n t i l th e y f i n d a h ig h and u n o b s t r u c t e d
p o i n t on th e p l a n t from which to ta k e o f f .
I t i s p r o b a b le t h a t ih e y do n o t f e e d be tw een a d u l t m oult
and f l i g h t , s i n c e an a l a t a w hich i s a b o u t to f l y w eighs c o n s id e r a b ly
l e s s th a n one w hich h a s j u s t m o u l ted . The d i f f e r e n c e a p p e a r s to
be due to w a te r l o s s a s shown by th e r e g r e s s i o n o f d ry w e ig h t ( y )
on l i v e w e ig h t (X) f o r newly m o u lted im m ed ia te ly p r e f l i g h t a l a t a e
( F ig u re 10 ) . The e q u a t io n s f o r th e r e g r e s s i o n a r e ;
Y = 0 .338X - 0 .1 7 3 (1 )
f o r newly m o u l ted a l a t a e and
Y * 0.356X - 0.07-4 (2 )
f o r p r e f l i g h t a l a t a e .
SfcA A l l th e a l a t a e were t a k e n from th e same p o p u la t i o n on th e
same day . Over th e whole ran g e o f w e ig h ts th e a l a t a e l o s e th e same
q u a n t i t y o f w a te r so t h a t sm a l l a l a t a e s u f f e r a much g r e a t e r
w a te r l o s s r e l a t i v e to w e ig h t ( com parison o f s lo p e s o f e q u a t io n s
1 and 2, t = 0 .0 5 3 2 , d . f . = 14> n o t s i g n i f i c a n t ) . An a l a t a
w e ig h in g 1 .5 mg a t b i r t h l o s e s 33$> o f i t s l i v e w e igh t w hereas
F ig u r e 9 &• A la ta e o f M. v i c i a e about; to f l y .
b . A la t a o f M. v i c i a e w hich h a s begun to
r e p ro d u c e w i th o u t f l i g h t w i th an a p t e r a
and l a r v a e .
F ig u r e 10 . R e g r e s s io n o f d ry w e ig h t ( mg ) on l i v e w e ig h t
(• 'tng ) f o r a l a t a e r e a r e d i n c row ds w hich have j u s t
m o u l te d ( o ) and w hich a r e a b o u t to f l y ( • ) .
' / -J|| pS <, ? V
Bui> X jp
AND NON-FLIERS
The s i z e o f th e c o rp u s a l l a tu m o f a p t e r o u s i n d i v i d u a l s
o f B. b r a s s i c a e was found to be tw ic e a s l a r g e a s t h a t o f a l a t a e
a t im a g in a l m ou lt ( W hite , 1965 )•
M easurem ent o f th e c o r p o r a a l l a t a , by a s t e r e o l o g i c te c h n iq u e
( F r e e r e & W ieb e l , 1967 )> o f crowded and i s o l a t e d t e n e r a l a l a t a e ,
i . e . p o t e n t i a l f l i e r s and n o n - f l i e r s , i n d i c a t e d no d i f f e r e n c e i n
s i z e o f th e c o rp u s a l l a tu m o f th e two ty p e s o f a l a t a e ( T ab le 4 )•
D i f f e r e n c e s be tw een f l i e r s and n o n - f l i e r s a r e th u s n o t e x p re s s e d
i n te rm s o f c o rp u s a l l a tu m volume i n th e t e n e r a l an im a l .
T a b le 4 » Mean r e l a t i v e s i z e i n s t e r e o l o g i c u n i t s ( m )
and s t a n d a r d d e v i a t i o n o f th e mean ( s ) o f c o rp o ra
a l l a t a o f i s o l a t e d t e n e r a l and crowded t e n e r a l
a l a t a e o f M. v i c i a e . The two b a t c h e s o f d a t a ( s i z e J ) a re
com pared u s i n g an F - t e s t o f v a r i a n c e .
m N _s
I s o l a t e d t e n e r a l
a l a t a e 3 2 .1 42 6 .1
Crowded t e n e r a l
a l a t a e 2 9 .8 50 6 .0
c
F = 1 .0 4 2 ( d . f . = 41 /49 ) n o t s i g n i f i c a n t
3 ( e ) . LIGHT AND ELECTRON MICROSCOPE STUDIES OF
FLIGHT MUSCLE
The c o n d i t i o n o f th e d o r s o - v e n t r a l i n d i r e c t f l i g h t m u sc les
o f f l y i n g and n o n - f l y i n g a l a t a e was s t u d i e d u s i n g b o th l i g h t
and e l e c t o n m ic ro s c o p e s .
L i g h t m ic ro s c o p y .
D u r in g th e t e n e r a l p e r io d a l a t a e r e a r e d i n crowds and i n 0
i s o l a t i o n a p p e a r , u n d e r th e l i g h t m icroscope to have i d e n t i c a l l y
i n t a c t w ing m u sc le s ( F ig u r e s 1 1 a - 14a ) . Flown a l a t a e which have
s e t t l e d f o r 24 h o u r s show a d e c re a s e i n th e t h i c k n e s s o f th e
m u s c le s v iew ed i n t r a n s v e r s e s e c t i o n . By th e end o f th e second day
a f t e r s e t t l i n g t h i s i s v e ry marked ( F ig u r e s 11a, b ) . Seven days
a f t e r s e t t l i n g th e i n d i r e c t f l i g h t m uscle h a s d i s a p p e a re d c o m p le te ly .
In n o n - f l y i n g a l a t a e , d e g e n e r a t io n o f th e i n d i r e c t f l i g h t
m u s c le s a p p e a r s to p ro c e e d a t th e same r a t e . As f l i g h t u s u a l l y
o c c u r s a b o u t 24 h o u r s a f t e r a d u l t m o u l t , 72 h o u rs a f t e r th e a d u l t
m o u l t o f n o n - f l i e r s ( F ig u re 12b ) i s ta k e n to be e q u i v a l e n t
t o 48 h o u r s a f t e r s e t t l i n g i n f l i e r s ( F ig u re l i b ) .
I n a l a t a e t h a t f l y th e breakdown o f f l i g h t m uscle s t a r t s
w i t h i n th e f i r s t day a f t e r s e t t l i n g . T h is d i f f e r s somewhat from
p r e v io u s f i n d i n g s where i n M. v i c i a e K a l t t h e r e was no h i s t o l o g i c a l
F ig u r e 11 . a . T r a n s v e r s e s e c t i o n th ro u g h th e d o r s o - v e n t r a l
i n d i r e c t f l i g h t m u sc le s o f a t e n e r a l crow ded
a l a t a o f M. v i c i a e .
( m = m usc le ) ( x 180 )
h . T r a n s v e r s e s e c t i o n th ro u g h th e d o r s o - v e n t r a l
i n d i r e c t f l i g h t m u sc le s o f a. f l i e r 2 days o '
a f t e r s e t t l i n g . ( x 180 )
F ig u r e 12 . a . T r a n s v e r s e s e c t i o n th ro u g h th e d o r s o - v e n t r a l
i n d i r e c t f l i g h t m u sc le s o f a t e n e r a l i s o l a t e d
a l a t a o f M. v i o i a e .
( m = m usc le ) . ( x 180 )
o
b . T r a n s v e r s e s e c t i o n th ro u g h th e d o r s o - v e n t r a l
i n d i r e c t f l i g h t m u sc les o f a n o n - f l i e r 2 day s
a f t e r s e t t l i n g . ( x 180)
F ig u r e 13- a . L o n g i t u d i n a l s e c t i o n th ro u g h a crow ded
t e n e r a l a l a t a o f M. v i c i a e show ing a
l o n g i t u d i n a l s e c t i o n o f th e d o r s o - v e n t r a l
i n d i r e c t f l i g h t m usc le ( m ) .
( x 110 )
b . L o n g i tu d in a l s e c t i o n th ro u g h a f l i e r 2
d ay s a f t e r s e t t l i n g show ing d e g e n e r a t i o n i n
th e d o r s o - v e n t r a l i n d i r e c t f l i g h t m u sc le s
( m ) . ( x 110 )
F ig u r e 14* a . L o n g i tu d in a l s e c t i o n th ro u g h a t e n e r a l
i s o l a t e d a l a t a o f M. v i c i a e show ing th e
d o r s o - v e n t r a l i n d i r e c t f l i g h t m u sc le s ( m_ )
i n l o n g i t u d i n a l s e c t i o n .
( x 110 )
b. Longitudinal section through an isolated alata of M. viciae 3 days after moult. The muscle ( m ) showsc signs of degeneration.
( x 110 )
e v id e n c e o f breakdow n u n t i l th e t h i r d day a f t e r s e t t l i n g
( Jo h n so n , 1957 )• The i n d i r e c t f l i g h t m uscle i n M. v i c i a e
a l a t a e r e a r e d i n i s o l a t i o n a p p e a r s to be i n t a c t u n t i l a t l e a s t 12
h o u r s a f t e r th e a d u l t m oult ( F ig u re 2a ) . I n 42 o f th e s e t e n e r a l
i s o l a t e d a l a t a e no e v id e n c e o f m uscle breakdown was found .
E l e c t r o n m ic ro s c o p y .
A more d e t a i l e d e x a m in a t io n o f th e d o r s o - v e n t r a l i n d i r e c t o
f l i g h t m u s c le s was c a r r i e d o u t u s in g an e l e c t r o n m ic ro sco p e .
The r a t i o o f m i to c h o n d r i a l a r e a to m uscle a r e a and a l s o 2
th e mean c r o s s - s e c t i o n a l ^ a r e a o f th e muscle f i b r i l s i n ji f o r
eac h spec im en were c a l c u l a t e d .
The d i f f e r e n c e s e x p e c te d in th e r e s u l t s were changes i n th e
s i z e o f th e m uscle f i b r i l s (m) due to e r o s io n o f myosin from th e
e d g e s ( e ) ( F ig u re 15b ) , changes i n th e numbers o f m i to c h o n d r ia
( s ) ( F ig u r e J 5 a ) and in t h e i r s i z e . Changes o f t h i s n a t u r e a re
r e p o r t e d when th e r e t r a c t o r u n g u is muscle o f th e l o c u s t i s
d e n e r v a t e d ( R ees , 1971 )• The tim e s c a l e i n th e l o c u s t i s much
g r e a t e r ( a f t e r 'JO days 20^ o f th e m uscle s t i l l rem ains ) th a n
in th e i n d i r e c t f l i g h t m uscle o f M. v i c i a e ( a f t e r 7 days a l l th e
m uscle h a s gone ) . F i r s t s i g n s o f d e g e n e ra t io n i n th e l o c u s t
a r e in t h e n e rv e e n d in g s ( R ees, 1971 )• Only two n e rv e end ings
were fo u n d i n th e M. v i c i a e p r e p a r a t i o n s and so changes i n th e
m uscle o n ly a r e c o n s id e r e d h e r e .
The ab dom ina l i n t e r s e g m e n t a l m usc les o f th e moth, A n th e rae a
p e r n y i , d e g e n e r a t e w i t h i n 48 h o u rs o f th e a d u l t moult ( Locksh in
& W i l l i a m s , 1 9 6 5 a ) . As e a r l y a s th e 5 th ho u r a f t e r a d u l t moult
th e f i r s t t r a c e s o f d e g e n e r a t io n a r e seen as s c a t t e r e d a r e a s o f
e r o s i o n o f th e m y o f i b r i l s and a s l i g h t c o n t r a c t i o n o f th e m ito ch o n d r i
A f t e r 15 h o u r s th e m uscle i s red u ce d i n volume to abou t one t h i r d ,
th e m y o f i b r i l s a r e d i s o r g a n i s e d and many o f th e m yofi lam en ts
p re su m ab ly d e s t r o y e d by ly s o s o m e - l ik e b o d ie s . The n u c l e i have
become p y c n o t i c .-and th e m i to c h o n d r ia a r e g r e a t l y shrunken and
d e g e n e r a t e . D u r in g th e d e g e n e r a t io n p ro c e s s l i p i d d e p o s i t s a re
o b s e rv e d n e a r th e m i to c h o n d r ia . Breakdown o f th e abdom inal
i n t e r s e g m e n t a l m u s c le s i n A. p e rn y i h as been shown to be a hormonal
p r o c e s s p r im ed d u r in g pupa l l i f e and t r i g g e r e d o f f by a sudden h a l t
o r d e c r e a s e i n th e m oto r n e rv e a c t i v i t y to th e in t e r s e g m e n ta l
m u sc le s . The m u s c le s a r e c a p a b le o f r e sp o n d in g to t h i s change in
n e rv o u s i n f o r m a t i o n d u r in g th e t h r e e days p r i o r to e c d y s i s ( Lockshin
& W i l l i a m s , 1964, 1965b) .
The breakdow n o f th e wing m usc les i n M. v i c i a e a p p e a rs to be
more s i m i l a r to t h a t i n A. p e rn y i th a n to th e d e g e n e ra t io n due to
d e n e r v a t io n i n l o c u s t .
F ig u r e 15* a. Transverse section of the dorso-ventral indirect flight muscle of a flier 24 hours after moult showing muscle fibrils ( m ) and mitochondria ( .s ). ( x 12,000 )
b. Transverse section of the dorso-ventral indirect flight muscle of a flier 48 hours after settling showing degenerating muscle fibrils ( m ), degenerating mitochondria ( ds ), a few small intact mitochondria ( a ) and erosion of myosin from the outer edge of the muscle fibrils ('©.)•
( x 12,000 )
F ig u r e 1 6 . a . T r a n s v e r s e s e c t i o n o f th e d o r s o - v e n t r a l
i n d i r e c t f l i g h t m usc le o f a n o n - f l i e r 24
h o u r s a f t e r m o u l t . The m usc le f i b r i l s ( m )
a r e i n t a c t b u t th e m i to c h o n d r i a ( j3 ) a r e n o t
a s t i g h t l y p ack ed t o g e t h e r a s i n th e m usc le
o f a f l i e r o f th e same age ( F ig u r e 5a ) .
( x 1 2 ,0 0 0 )
b . T r a n s v e r s e s e c t i o n th ro u g h th e d o r s o -
v e n t r a l i n d i r e c t f l i g h t m uscle o f a n o n - f l i e r
72 h o u r s a f t e r m o u lt show ing d e g e n e r a te d
m usc le f i b r i l s ( m ) , d e g e n e r a t i n g
m i to c h o n d r i a ( ds ) and a few i n t a c t
m i to c h o n d r i a ( j3 ) . ( x 1 2 ,0 0 0 )
>imMmi
and non-fliers at different times after adult moult.
mean
mean
FLIERS NON-FLIERS Within 12 hours of moult.
2mito/musc muse \i mito/musc 2muse p. 0 . 7 0 2.56 1.15 2 .9 k 0.55 2.53 0.66 2.33 1.01 2.99 0.91 2 .2 k 0.60 3.52 0.90 1.70 • 0.75 2.66 0.91 2.50
Within 2k hours of moult (i.e. time of flight for fliers).
p <mito/musc muse p, mito/musc muse \ i
0.89 U. 12 0.61+ 3.23 1.12 3.31 0.7U 2.29 1.07 3.32 0.75 3.28 0.86 2 .3 k 0.79 2.70 0.89 2.18 O.Gk 1.90 0.80 2 .5 k 1 . I k 2 .k2
0.71 1.86 1.12 1.62 1.00 2 .k 0
0.97 2.61 0.71 2.68
PLIERS NON-FLIERS 4 hours after settling.
mito/musc muse u. mito/musc muse 0.53 5.02 0.70 3.81 0.61 1.64 0.88 1.61 0 .7 0 1.88 0.69 2.73 1.03 3.35 0.70 1.33 0.61 2.34 0.74 r 2.48 0.72 2.62
One day after settling, 48 hours from moult. 2 2 mito/musc muse nt mito/musc muse n
0.90 2.33 0.88 2.55 0.96 2.68
0.91 2 .68
0.03 0.63 0.17 0.U6 0.11 0.85
0 .1 0 0.65
0.13 1.25
As l i t t l e a s 4 t o u r s a f t e r s e t t l i n g a s i g n i f i c a n t d e c re a s e
( P ^ 0 .0 1 ) i s s een i n th e m i to c h o n d r ia /m u s c le a r e a r a t i o o f
f lo w n a p h id s ( T ab le ) a l th o u g h no d e c re a s e i n th e s i z e o f th e
m u sc le b u n d le s i s a p p a re n t a t t h i s t im e . Two days a f t e r s e t t l i n g
t h e m usc le f i b r i l s have d e c re a se d to 50$ o f t h e i r o r i g i n a l c r o s s -
s e c t i o n a l a r e a and th e m i to c h o n d r ia a re much red u ce d i n number and
s i z e ( T a b le 5* F ig u r e s 15a, b ) . Myosin i s l o s t from th e edges o f
t h e m usc le b u n d le s (e_, F ig u re 15b ) .
12 h o u r s a f t e r a d u l t m oult th e wing m u sc u la tu re o f a l a t a e
r e a r e d i n crowds and i n i s o l a t i o n i s th e same i n te rm s o f m i to c h o n d r ia
a n d m usc le ( T ab le 5 )• A phids r e a r e d i n i s o l a t i o n , however, do
n o t p o s s e s s a s g r e a t a number o f m i to c h o n d r ia i n t h e i r w ing m uscles
2 4 h o u r s a f t e r m ou lt a s do t h e i r f l y i n g c o u n t e r p a r t s o f th e same
a g e ( P < 0 .0 1 ) ( T ab le 5> F ig u r e s 15a, i 6 a ) .
A lth o u g h th e l i g h t m icroscope s t u d i e s ‘’r e v e a l a d e c re a se i n
t h e m usc le s i z e i n n o n - f l i e r s 48 h o u rs a f t e r m oult th e n o n - f l y i n g
a p h i d s u s e d f o r e l e c t r o n m icroscopy showed no change in muscle
f i b r i l s i z e from 12 h o u rs to 48 h o u rs a f t e r a d u l t moult ( T ab le 5 )•
The more advanced s t a t e o f breakdown o f th e m uscle f i b r i l s
i n n o n - f l i e r s 72 h o u r s a f t e r m oult compared w i th f l i e r s which
h av e s e t t l e d f o r 2 days s u g g e s t s t h a t th e d e g e n e ra t io n i s i n i t i a t e d
b e f o r e th e end o f th e f i r s t day a f t e r th e a d u l t m oult ( F ig u re s 15b,
16b ) . I n f l i e r s th e i n i t i a t i o n o f breakdown i s d e la y e d u n t i l
a f t e r s e t t l i n g .
The tim e r e q u i r e d to com ple te th e l o s s o f i n d i r e c t f l i g h t
m uscle i n M. v i c i a e i s l o n g e r ( abou t 7 days ) th a n th e 2 days
n e c e s s a r y f o r th e d is a p p e a ra n c e o f th e abdom inal in t e r s e g m e n ta l
m u s c le s o f A. p e r n y i . However, w i th in 72 h o u rs o f m oult th e
m uscle f i b r i l s o f f l i e r s have been red u ced to 50$ o f t h e i r o r i g i n a l
volume and th o s e o f n o n - f l i e r s to 25$ o f t h e i r o r i g i n a l volume
( T ab le 5, F ig u re 17 ) . Most o f t h i s l o s s h a s ta k en p la c e between c ,.v .
48 and 72 h o u rs a f t e r moult so t h a t th e r e d u c t io n o f th e f l i g h t
m u sc le s i n M. v i c i a e i s v e ry s i m i l a r i n te rm s o f tim e to t h a t o f
th e abdom inal in te r s e g m e p . ta l m usc les o f A. p e r n y i .
A lth o u g h t h e r e i s no e v id e n c e a f t e r 2 days o f e i t h e r th e
l i p i d d e p o s i t s w i t h i n the m uscle o r o f th e ly s o s o m e - l ik e b o d ie s
r e p o r t e d i n th e p e r n i i d moth ( L ocksh in & W il l iam s , 1965a ) i t i s
p r o b a b le t h a t d e g e n e r a t io n i s s i m i l a r l y c o n t r o l l e d i n b o th c a s e s .
I n A. p e r n y i j u v e n i l e hormone i s b e l i e v e d to p r e v e n t muscle
breakdow n u n t i l a f t e r th e a d u l t m oult ( L ocksh in & W il l ia m s , 1964 ) .
A s i m i l a r p r o t e c t i v e system may o p e r a t e d u r in g th e t e n e r a l p e r io d
i n M. v i c i a e so t h a t a f t e r abou t 24 h o u rs , u n l e s s f l i g h t o c c u r re d ,
m uscle breakdown would b e g in . When m otor im p u lse s to th e wing
m u sc le s c e a s e , a s would happen when f l y i n g a p h id s s e t t l e , o r i f
t h e m uscle n e v e r r e c e i v e s any in fo rm a t io n from th e n e rv o u s system ,
a s may be th e c a s e w i th a p h id s which do n o t f l y , m uscle d e g e n e ra t io n
F ig u r e 17* H is .togram s show ing w here s i g n i f i c a n t
ch a n g e s o c c u r i n m u sc le f i b r i l c r o s s -
s e c t i o n a l a r e a and i n m i t o c h o n d r i a l /
m usc le a r e a r a t i o d u r i n g f l i g h t m usc le
breakdow n i n f l y i n g and n o n - f l y i n g a l a t a e 'O
o f M. v i c i a e .
m us
cl e
fi br
il t.
s. ar
vXvXv
l i i w x v.v.; XvX
§ ' S
i l l i i
hour* hour. a f te r 12 2 4 after 48 moult fettling
x3*XAV.V.V :: A
w.wa sss:s
i i f
28.
w ould be i n i t i a t e d .
Although, some a l a t a e o f M. v i c i a e do n o t f l y th ey a l l p o s s e s s
i n t a c t w ing m u sc le s a t l e a s t up to 12 h o u rs a f t e r th e a d u l t m ou lt .
The d e g e n e r a t i o n p r o c e s s s t a r t s a t th e end o f th e t e n e r a l p e r io d
( 24 h o u r s ) i n n o n - f l i e r s and im m ed ia te ly a f t e r s e t t l i n g in
f l i e r s .
3(f). REPRODUCTIVE RATES AND WEIGHTS OF LARVAE
S in c e n o n - f l y i n g a l a t a e o f M. v i c i a e a r e s t r u c t u r a l l y
i d e n t i c a l to th o s e which f l y t h i s s p e c ie s p r e s e n t s th e i d e a l
s i t u a t i o n f o r an i n v e s t i g a t i o n o f th e e f f e c t o f f l i g h t on
r e p r o d u c t i v e c a p a c i t y .
Newjy m o u lted a p t e r o u s , and newly m oulted flown and unflow n
a l a t a e o f M. v i c i a e were i s o l a t e d on bean s e e d l i n g s . A p te ra e ,
f l i e r s and n o n - f l i e r s were w eighed on th e f i r s t day o f r e p r o d u c t io n . G
The l a r v a e p roduced each day by each m other were c o u n te d , th e d a y ' s
p r o d u c t i o n o f each m other w eighed as one b a tc h and th e mean w e ig h t
o f l a r v a e p ro d u ced by each ap h id each day c a l c u l a t e d .
A f t e r 20 days 70# o f th e a p t e r a e , 4 2 .2 # o f th e f l i e r s and
4 2 .5 # o f th e n o n - f l i e r s were s t i l l a l i v e . Thus f l i g h t does n o t
a f f e c t th e l o n g e v i t y o f a l a t a e b u t t h e r e was a much h ig h e r m o r t a l i t y
r a t e among th e a l a t a e th a n among th e a p t e r a e . T h is s i t u a t i o n i s
d i f f e r e n t from t h a t i n A. f a b a e . A la ta e o f A. fab ae r e a r e d s i n g l y
i n th e l a b o r a t o r y l i v e j u s t a s lo n g as a p t e r a e ( Dixon & W ra t te n ,
1971 )•
The numbers o f l a r v a e (Y) p roduced by a p t e r a e and n o n - f l i e r s
do n o t v a ry s i g n i f i c a n t l y w i th th e w e ig h t o f th e m other (X) d u r in g
any o f th e 5 day p e r io d s from days 1 to 20 o f r e p r o d u c t iv e l i f e
F ig u r e 18. num bers o f l a r v a e p ro d u c e d
d u r i n g day s 1 -5 ( a ) , 6 -10 ( b ) , 1 1 - 1 5
( c_ ) and 16 -2 0 ( .d ) p l o t t e d a g a i n s t
m a te r n a l w e ig h t ( mg ) m easu red on th e
f i r s t day o f r e p r o d u c t i o n .
n°n-fllers
of 1 °nothor
T ab le 6 . R e g re s s io n fo rm u lae and th e s i g n i f i c a n c e o f th e d e v i a t i o n
from z e ro o f th e r e g r e s s i o n c o e f f i c i e n t s f o r th e r e l a t i o n s h i p
be tw een th e number o f a p h id s (Y) p roduced by a p t e r a e , f l i e r s and
n o n - f l i e r s w i th i n days 1 - 5 » 6 - 1 0 , 11 - 15 and 16 - 20 o f
r e p r o d u c t i v e l i f e and th e w e ig h t o f th e m other i n m i l l i g r a m s (X ).
The common r e g r e s s i o n c o e f f i c i e n t i s g iv en f o r each group .
A p te ra e S ig . o f
- No. o f * d e v i a t i o n o f Common p e r i o d R e g re s s io n fo rm u la r e g r e s s , c o e f f . r e g r .
m o the rs from ze ro c o e f f .
1 13 Y = 1.015X + 26 .883 N.. S. 1 .767
2 13 Y = O .76X + 23 .358 N. S.
3 13 Y = 1.068X + 21.285 N. S.
4 13 Y = 4.225X + 2 .796 N. S.
F l i e r s
1 14 Y = 7.219X + 2 .763 0 . 0 1
2 14 Y = 5 . 251X + 6 .993 0 . 1 0
3 9 Y = 4 0 .3 0 9 - 5.225X N. S
4 7 Y = 2.842X — 1.027 N. S
6 .119
2 8 Y = 3 . 288X + 16.432 N. S
3 6 Y = 36.342 - 3 . 342X N. s
4 5 Y = 0.107X + 13.152 N. s
- 0 .0 1 9
T ab le 7 « R e g r e s s io n fo rm u lae f o r th e r e l a t i o n s h i p betw een th e
num bers o f l a r v a e (Y) p roduced by a p t e r a e , f l i e r s and n o n - f l i e r s
d u r i n g d ay s 1 - 5 ? 6 - 10, 11 - 15 and 16 - 20 o f r e p r o d u c t iv e l i f e
and th e w e ig h t o f th e m other i n m i l l ig r a m s (X) r e c a l c u l a t e d u s in g
th e common r e g r e s s i o n c o e f f i c i e n t s from T able 6.
A p te ra e
P l i e r s
5 day p e r i o d R e g re s s io n fo rm u la u s i n g C.R.C.
N o n - f l i e r s
Y = 23 .88 + 1.77X
Y = 19 .34 + 1.77X
Y = 18 .50 + 1.77X
Y = 12 .58 + 1.77X
Y = 4 .48 + 6.12X
Y = 26 .34 + 1.68X
Y = 21 .84 + 1.68X
Y = 19 .25 + 1.68X
Y = 7*59 + 1.68X
( T a b le 6, F ig u re 18 ) , However, l a r g e a l a t a e which f l y produce
s i g n i f i c a n t l y more l a r v a e th a n sm all flown a l a t a e du ring - th e f i r s t
t e n day s o f r e p r o d u c t i v e l i f e ( days 1 -5 ; t * 3 .786 , d . f . = 12,
P < 0 .0 1 and days 6 -1 0 ; t = 2 .1 2 7 , d . f . = 1 2 , P < 0 .1 0 ) ( Tab le 6 )
T here a r e d i f f e r e n c e s in e l e v a t i o n o f th e r e g r e s s i o n l i n e s
( T ab le 6 ) and t h i s i s made c l e a r e r by r e c a l c u l a t i n g each l i n e
u s i n g th e common r e g r e s s i o n c o e f f i c i e n t . The r e s u l t i n g r e g r e s s i o n s
f o r t o t a l number o f l a r v a e p roduced i n a f i v e day p e r io d (Y) a g a i n s t
th e w e ig h t o f th e m other (X) a r e shown i n T ab le 7« From
c o m p a r iso n s o f th e r e g r e s s i o n l i n e s c a l c u l a t e d u s in g th e common
r e g r e s s i o n c o e f f i c i e n t f o r a p t e r a e and n o n - f l i e r s t h e r e ap p e a rs to
be no s i g n i f i c a n t d i f f e r e n c e i n th e numbers p roduced by th e two
morphs d u r i n g th e f o u r f i v e day p e r io d s ( Tab le 1 i n A ppendix 2 ).
A v e ry marked f a l l - o f f i n l a r v a l p r o d u c t io n i s seen in
th e l a s t 5 day p e r i o d f o r f l i e r s when compared w ith a p t e r a e
( F ig u r e 18, T ab le 1 i n A ppendix 2 ) . D uring days 15 to 20 the
num bers o f l a r v a e p ro d u ced by a p t e r a e and n o n - f l i e r s a l s o f a l l s
o f f b u t n o t a s d r a s t i c a l l y a s f o r f l i e r s ( T ab le 1 i n Appendix 2 ) .
N o n - f l i e r s p roduce few er l a r v a e th a n a p t e r a e d u r in g days 15 to 20
and more th a n f l i e r s d u r in g t h i s t im e . The d i f f e r e n c e s , however,
a r e n o t s i g n i f i c a n t ( T ab le 1 i n Appendix 2 ) . A p te rae and non­
f l i e r s and th o s e f l i e r s which weigh more th a n 3 .0 mg p roduce
th e g r e a t e s t number o f l a r v a e d u r in g th e f i r s t 5 day p e r io d .
Sm all f l i e r s p roduce th e l a r g e s t numbers d u r in g th e t h i r d 5 day
p e r io d ( F ig u r e 18 ) .
Thus a l th o u g h lo n g e v i ty i n a l a t a e i s n o t a f f e c t e d by f l i g h t ,
f l y i n g d o es seem to c o s t an a l a t a a l a r g e p r o p o r t i o n o f i t s
p o t e n t i a l l a r v a p r o d u c t i o n . A f t e r f l i g h t l a r v a p ro d u c t io n by sm all
a l a t a e i s d i s t r i b u t e d d i f f e r e n t l y i n t im e . A l a r g e r p r o p o r t i o n o f
l a r v a e a r e p ro d u ced by sm all f l i e r s d u r in g days 6 to 15 o f
r e p r o d u c t i v e l i f e th a n by l a r g e f l i e r s , a p t e r a e and n o n - f l i e r s
o v e r th e same p e r io d .
The r e g r e s s i o n e q u a t io n s f o r mean l a r v a l w e igh t a g a i n s t
m a te r n a l w e ig h t were r e c a l c u l a t e d u s in g th e common r e g r e s s i o n
c o e f f i c i e n t ( T ab le 11 ) . The r e s u l t i n g e q u a t io n s a r e r e p r e s e n t e d
i n F ig u r e 19* A f t e r th e f i r s t te n days th e mean w e igh t o f l a r v a e
p ro d u ced by a p t e r a e f a l l s from 0 .1 4 mg to 0 .1 3 mg ( F ig u re 19>
T ab le 2 i n A ppendix 2 ) . N o n - f l i e r s p roduce th e s m a l l e s t l a r v a e
d u r in g t h e f i r s t 5 day p e r io d . L a rg e r l a r v a e a r e p roduced d u r in g
d ays 6 to 10 and th e l a r g e s t d u r in g th e second h a l f o f th e
r e p r o d u c t i v e p e r i o d . In f l i e r s a l s o th e s m a l le s t l a r v a e a r e
p ro d u ced f i r s t . I n A. fab ae th e w e igh t o f l a r v a e p roduced by
a l a t a e i n c r e a s e w i th tim e w h ile th o se p roduced by a p t e r a e
rem a in t h e same ( Dixon & W ra t te n , 1971 )•
I f l a r v a l p r o d u c t io n i s c a l c u l a t e d a s th e t o t a l mass o f
l a r v a l t i s s u e p ro d u ced by an a p h id d u r in g days 1 to 5» 6 to 10,
Table 8. Total mass of larvae (mg) produced by 2.5 mg and 3*5 mg apterae, fliers and non-fliers during days 1 - 5? 6 - 1 0 , 11 - 1 5 and 16 - 20 of reproductive life.
Weight of mother (mg)
APTERAE 2.5 3.5
FLIERS 2.5 3.5
NON-FLIERS 2.5 3.5
Total mass of larvae (mg) Days Days Days Days Total 1 - 5 6-10 11-15 16-20
WPMlMMM 1 nif tsm iwlli
4.485 3.198 3.133 1.585 4.298 3.513 3.279 2.235
12.401
13.325
9.086 10.992
12.717 12 .000
F i g u r e 19 . Mean l a r v a l w e ig h t ( mg ) d u r i n g days
i - S . i a ) , 6 -1 0 ( h ) . 1 1 - 1 5 ( £ ) and
1 6 -2 0 ( d ) p l o t t e d a g a i n s t m a te rn a l
w e ig h t ( mg ) m easu red on th e f i r s t day
o f r e p r o d u c t i o n f o r a p t e r a e , f l i e r s and
n o n - f l i e r s .
fliersap te rae
5 day period
T a b le 9 . R e g r e s s io n fo rm u lae and th e s i g n i f i c a n c e o f th e d e v i a t i o n
from z e ro o f th e r e g r e s s i o n c o e f f i c i e n t s f o r th e r e l a t i o n s h i p s
b e tw e e n th e mean w e ig h t o f i n d i v i d u a l l a r v a e (Y) p roduced by a p t e r a e ,
f l i e r s and n o n - f l i e r s d u r in g days 1 - 5> 6 - 10, 11 - 15 and 16 - 20
o f r e p r o d u c t i v e l i f e and th e w e igh t o f th e m other i n m i l l ig r a m s (X ).
The common r e g r e s s i o n c o e f f i c i e n t i s g iven f o r each group .
5 day p e r i o d No. o f
m o the rs R e g re s s io n fo rm u la
S ig . o f d e v i a t i o n
o f r e g r . c o e f f .
Common
A p te ra e
1 13 Y = -0 .180 - 0.011X 0 .0 5 0
- 0 .00025
4 13 Y = 0 .1 1 4 + 0.004X N. S.
P l i e r s
1 14 Y = 0 .1 1 4 + 0.001X N. S. 0 .0039
2 14 Y = 0 .1 1 6 + 0.004X N. S.
3 14 Y = 0 .072 + 0.018X N. S.
4 14 Y = 0 .195 - 0.021X N. S.
N o n - f l i e r s
1 9 Y = 0 .149 - 0.011X N. S. - 0 .0 1 9 3
2 8 Y = 0 .1 5 3 - 0.009X N. S.
3 6 Y = 0 .264 - 0.039X 0 .1 0
4 6 Y = 0 .241 - 0.034X 0 .1 0
Table 10. days 1 - 5 ,
life by 2.5
-2 .5
3 .5
Mean weight of larvae (mg) produced during 6 - 1 0 , 11 - 1 5 and 16 - 20 of reproductive mg and 3*5 mg apterae, fliers and non-fliers.
Mean weight of larvae (mg) Days Days Days Days
1 - 5 6 - 1 0 11-15 16 - 2 0
0 .1 5 3 0 .127 0.13U 0.121+
0.11+2 0.131+ 0 .133 0.128
0 .117 0.126 0 .117 0.11+3
0.118 0 .130 0 .135 0 .122
0 .1 2 2
0 . 1 2 2
T ab le 1 1 . R e g r e s s io n fo rm u lae f o r th e r e l a t i o n s h i p betw een th e
mean w e ig h t o f l a r v a e (Y) p roduced by a p t e r a e , f l i e r s and n o n - f l i e r s
d u r in g d ay s 1 - 5> 6 - 10, 11 - 15 and 16 - 20 o f r e p r o d u c t iv e
l i f e and th e w e ig h t o f t h e m other i n m i l l ig r a m s (X) r e c a l c u l a t e d
u s i n g t h e common r e g r e s s i o n c o e f f i c i e n t s from T ab le 9*
5 day p e r i o d R e g re s s io n formuba u s in g C.R.C
A p te ra e
1
Y = 0 .131 - 0.00025X
1
2
Y = 0 .115 + 0 .0039* Y » 0 .112 + 0.0039X
N o n - f l i e r s
1
2
Y = 0 .196 - 0.0193X
Y = 0 .192 - 0.0193X
32.
11 -to 15 and 16 to 20 o f i t s r e p r o d u c t iv e l i f e ( T ab le 8 ) to be
an a l a t a c o s t s a 3*5 mg ap h id ro u g h ly 10$ o f i t s l a r v a p r o d u c t io n
( i . e . co m paring n o n - f l i e r s w i th a p t e r a e ) b u t u se o f i t s w ings
and w ing m u sc le s r e d u c e s th e l a r v a p ro d u c t io n o f a 2 . 5 mg a l a t a
t o 7 3 *27$ o f t h a t o f an a p t e r a and to 7 1 *45$ o f t h a t o f an a l a t a
w h ich do es n o t f l y . A 3 . 5 mg f l y i n g a l a t a p ro d u c e s 81 .9 7 $ o f th e
t o t a l mass p ro d u ced by an a p t e r a o f th e same w e ig h t and 9 1 *02$ o f
t h a t o f an e q u i v a l e n t n o n - f l i e r .
The much lo w er t o t a l mass o f l a r v a e p roduced by sm all flow n
a l a t a e d u r in g th e f i r s t te n days o f r e p r o d u c t io n i s due o n ly to
th e sm a l l numbers o f l a r v a e th e y produce ( F ig u re 19 ) . Mean
w e ig h t s o f l a r v a e from b o th f l y i n g and n o n - f l y i n g a l a t a e a r e
s i m i l a r d u r in g th e f i r s t t e n days ( T ab le 10 ) . D u r in g days 1 to 5
t h e l a r v a e p roduced by a p t e r a e a r e much l a r g e r ( 0 . 1 5 3 mg f o r a
2 . 5 mg m other and 0 . 1 4 2 mg f o r a 3*5 mg m other ) th a n th o s e
p ro d u c e d by a l a t a e w h e th e r th e y f l y o r n o t . At t h i s tim e th e r e
i s a s i g n i f i c a n t in v e r s e r e l a t i o n s h i p betw een mean w e ig h t o f
l a r v a e o f a p t e r a e and th e w e ig h t o f th e m other ( t = 2.394*
d . f . = 1 1 ,CP < 0 .0 5 )* D uring days 11 to 15 and 16 to 20 a
s i m i l a r r e l a t i o n s h i p e x i s t s f o r mean l a r v a l and m a te rn a l w e ig h ts
o f n o n - f l i e r s ( 1 1 -15 ; t = 2 .7 1 1 , d . f . = 4, P < 0 . 1 0 and 16- 2 0 ;
t * 2 .1 4 1 , d . f* = 4, P < 0 . 1 0 ) .
33.
L i f e t a b l e s were c o n s t r u c t e d ( T ab le 12 ) and th e n e t
r e p r o d u c t i o n r a t e , R^, was c a l c u l a t e d f o r sm a l l ( 2 .5 mg ) and
l a r g e ( 3 .5 mg ) a p t e r a e , f l i e r s and n o n - f l i e r s ( B i r c h , 1948 ) .
The s u r v i v a l r a t e ( 1 ) f o r th e im m ature s t a g e s i s assumed to
be one h u n d re d p e r c e n t f o r eac h g roup . C a l c u l a t i o n s w ere b a s e d
on th e num bers o f young p ro d u ced d u r in g each 5 day p e r i o d by
s m a l l and l a r g e a p t e r a e , f l i e r s and n o n - f l i e r s a s e s t i m a t e d from
th e r e g r e s s i o n fo rm u la e c a l c u l a t e d u s in g th e common r e g r e s s i o n
c o e f f i c i e n t ( T a b le 7 )•
The n e t r e p r o d u c t i o n r a t e which i s a m easure o f th e number
o f t im e s a p o p u l a t i o n w i th a s t a b l e age d i s t r i b u t i o n w i l l m u l t i p l y
i t s e l f i n one g e n e r a t i o n i s h i g h e s t i n a p t e r a e ( = 75*0 f o r
s m a l l a p t e r a e and 8 3 .2 f o r l a r g e a p t e r a e ) and i n n o n - f l i e r s
( Rq = 7 4 .1 f o r sm a l l n o n - f l i e r s and 79*0 f o r l a r g e n o n - f l i e r s ) '
but v e r y much lo w e r i n f l i e r s ( R^ = 60 .9 f o r sm all f l i e r s and
68*2 f o r l a r g e f l i e r s ) ( T ab le 12 ) .
More a c c u r a t e p a ra m e te r s o f th e c a p a c i t y f o r i n c r e a s e o f
a. p o p u l a t i o n a r e th e i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e , r , which
i s a m easu re o f th e d i f f e r e n c e be tw een b i r t h and d e a th r a t e s i n
a p o p u l a t i o n , and A = a n t i l o g ^ r , which i s th e f i n i t e r a t e o f
i n c r e a s e o f th e p o p u la t i o n ( B i r c h , 1948 ) . These t a k e i n t o
a c c o u n t t h e l e n g t h o f tim e from b i r t h to m a t u r i t y , t h e t im e d u r in g
w hich r e p r o d u c t i o n o c c u r s and th e r e p r o d u c t iv e r a t e .
T a b le 1 2 . L i f e t a b l e s f o r p o p u l a t i o n s o f 2 .5 mg an& 3*5 mg a p t e r a e ,
f l i e r s and n o n - f l i e r s show ing th e n e t r e p r o d u c t i o n r a t e , R^, f o r
e a c h p o p u la t io n * S u r v iv a l r a t e s , (1^.), and r e p r o d u c t i v e r a t e s , ( mx )>
a r e ta k e n o v e r p e r i o d s o f 5 d ay s , th e mid p o i n t s o f w hich tim e
i n t e r v a l s a r e i n d i c a t e d by x .
X (m ) x' ( l m )' X X7 X ( m ) ' x 7 ( l m )' X X 2 .5 mg apterae 3.5 mg apterae
0 . 5 1 .0 0 0 0 .5 1 .0 0 0
1 .5 1 .0 0 0 1 .5 1 .0 0 0
2 .5 0 .9 5 28 26.6 2 .5 0 .95 30' 28 .5
3 .5 0 .90 23.6 20.7 3 .5 0 .90 25.5 23 .0
4 .5 0 .75 22.0 16 .5 4 .5 0 .75 24.5 18." 4
5 .5 0 .70 16.0 11 .2 5 .5 0 .70 19.0 1 3 .3 R - 75 .0 R = 83 .2
, 0 • O
2 .5 mg f l i e r s 3 .5 mg f l i e r s
0 .5 1 .0 0 0 0 .5 1 .0 0 0
1 .5 1 .0 0 0 1 .5 1 .0 0 0
2 .5 0 .95 22 20.9 2.5. 0 .95 28 26 .6
3 .5 0 .8 5 19.5 16.6 3.5 0 .85 26 22.1
4 .5 0 .70 26 .5 18.6 4 .5 0 .70 23.5 16 .5
5 .5 0 .40 12.0 4* 8 5 .5 0 .40 7 .5 3.0
R = 60.9 R = 68 .2 0 0
2 .5 mg n o n - f l i e r s 3 .5 mg n o n - f l i e r s
0 .5 c l.O - 0 0 0 . 5 1 .0 0 0
1 .5 1 .0 0 0 1 .5 1 .0 0 0
2 .5 1 .0 30.5 30.5 2 .5 1 .0 32:0 32.0
3 .5 0 .8 5 26.0 22.1 3 .5 O.85 27 .5 23 .4
4 .5 0 .67 23 .5 15.7 4 .5 0.67 25.0 1 6 .8
5*5 0 .50 11 .5 5 .8 5 .5 0 .50 13.5 6 .8
R0 = 74.1 R0 = 79 .0
34 .
The r v a l u e s f o r f l i e r s a r e n o t a s d i f f e r e n t from th o s e f o r
n o n - f l i e r s and a p t e r a e a s c o u ld he e x p e c te d from th e n e t r e p r o d u c t i o n
r a t e s , R ( T a b le s 12 and 13 ) . The n e t r e p r o d u c t i o n r a t e o f a
p o p u l a t i o n o f sm a l l f l i e r s i s 8 l $ o f t h a t o f a p o p u l a t i o n o f
s m a l l a p t e r a e and 82$ o f t h a t o f a p o p u la t i o n o f sm a l l n o p - f l i e r s *
A p o p u l a t i o n o f l a r g e f l i e r s h a s a n e t r e p r o d u c t i o n r a t e w hich i s
8 2 $ o f t h a t o f a p o p u l a t i o n o f l a r g e a p t e r a e and 86$ o f t h a t o f
a p o p u l a t i o n o f l a r g e n o n - f l i e r s ( T ab le 12 ) . The g r e a t e s t
d i f f e r e n c e i n i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e i s be tw een
p o p u l a t i o n s o f sm a l l f l i e r s and n o n - f l i e r s . The r v a l u e f o r sm a l l
f l i e r s i s 91% o f t h a t o f sm a l l n o n - f l i e r s ( T a b le 13 )•
F l i e r s a r e c a p a b le o f m aking good some o f th e n e t r e p r o d u c t i o n
r a t e d e f i c i t * The p e r c e n ta g e c o n t r i b u t i o n o f th e i n d i v i d u a l
5 day p e r i o d s to w a rd s th e i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e
( T a b le 14 ) i n d i c a t e s an e x p l a n a t i o n . D u r in g days 6 to 15 th e
r e p r o d u c t i v e r a t e o f sm a ll f l i e r s c o n t r i b u t e s 2 1 .5 3 $ to w a rd s
t h e v a l u e o f r and t h a t o f l a r g e f l i e r s c o n t r i b u t e s 1 9 *49$ to w a rd s
r d u r i n g t h i s t im e ( T ab le 14 )• Small a p t e r a e c o n t r i b u t e 18*75$
t o r d u r i n g t h i s t im e and l a r g e a p t e r a e 1 8 . 78$ . C'
A p o p u l a t i o n o f a l a t a e which do n o t f l y can com pensa te so w e l l
f o r t h e low v a lu e o f R t h a t th e p o p u la t io n h a s a much h i g h e r —o
i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e , r , th a n h a s a p o p u l a t i o n o f
a p t e r a e ( T ab le 13 ) . They p roduce more l a r v a e d u r in g th e f i r s t
5 d a y s o f t h e i r r e p r o d u c t i v e l i f e and so c o n t r i b u t e much more
T a b le 13 * I n t r i n s i c r a t e s o f n a t u r a l i n c r e a s e , r , and f i n i t e r a t e s
o f i n c r e a s e , A, f o r p o p u l a t i o n s , w i th s t a b l e age d i s t r i b u t i o n s , o f
a p t e r a e , f l i e r s and n o n - f l i e r s o f d i f f e r e n t w e ig h t s .
Apterae weight r A
3*5mS 1 .42 4.1.4
Fliers 2.5mg ' 1 .32 3 .74 3 . 5mg 1 .40 4 .06
Non-fliers 2 . 5mg
35 .
to w a r d s r than a p t e r a e do d u r i n g t h e same p e r i o d ( T ab le 14 ) .
P o p u l a t i o n s o f sm a l l a p t e r a e and n o n - f l i e r s have v e r y
n e a r l y t h e same n e t r e p r o d u c t i o n r a t e , Rq , ( T ab le 12 ) and a lm o s t
th e same i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e , r , ( T a b le 13 )
a s p o p u l a t i o n s o f l a r g e r i n d i v i d u a l s . They d i s t r i b u t e t h e i r
l a r v a p r o d u c t i o n i n t im e so t h a t eac h 5 day p e r i o d c o n t r i b u t e s
t h e same p e r c e n ta g e to w a rd s r ( T ab le 14 ) a s does th e e q u i v a l e n t
p e r i o d o f t im e f o r a p o p u l a t i o n o f th e l a r g e r a p h id s .
P o p u l a t i o n s o f sm a l l and l a r g e f l i e r s have v e r y d i f f e r e n t
R^ v a l u e s ( T ab le 12 ) and r v a l u e s ( T ab le 13 )• Sm all f l i e r s ,
c o n t r i b u t e o n ly 78% to w a rd s r d u r in g th e f i r s t f i v e d ay s com pared
w i th 8 0 .3 7 $ c o n t r i b u t e d by l a r g e f l i e r s . The lo w e r v a lu e o f
r f o r a p o p u l a t i o n o f sm all f l i e r s a r i s e s b e c a u se th e y p ro d u ce
a much s m a l l e r p r o p o r t i o n o f t h e i r l a r v a e d u r i n g th e f i r s t 5 day s
o f r e p r o d u c t i v e l i f e th a n do i n d i v i d u a l s i n a p o p u l a t i o n c o n s i s t i n g
o f l a r g e a p t e r a e , s m a l l a p t s r a e , l a r g e n o n - f l i e r s , sm a l l n o n - f l i e r s
o r l a r g e f l i e r s ( F ig u r e 18 ) . D u r in g days 11 to 15 sm a l l f l i e r s
p ro d u c e a r e l a t i v e l y l a r g e p r o p o r t i o n o f t h e i r o f f s p r i n g when
com pared w i th l a r g e r f l i e r s ( F ig u re 18 ) . T h is i s r e f l e c t e d
i n th e 4 .9 6 $ c o n t r i b u t i o n to r by a p o p u la t io n o f sm a l l f l i e r s
a t t h i s t im e com pared w i th 3 .0 3 $ f o r a p o p u la t io n o f l a r g e f l i e r s
( T a b le 14 ) . The p e r c e n ta g e c o n t r i b u t i o n to w ard s r f o r l a r g e
f l i e r s i s d i s t r i b u t e d o v e r th e f o u r 5 day p e r i o d s i n th e same
T a b le 1 4 . P e r c e n t a g e c o n t r i b u t i o n o f each f i v e , day p e r i o d to w a rd s
r i n p o p u l a t i o n s o f a p t e r a p , f l i e r s and n o n - f l i e r s o f d i f f e r e n t
w e ig h t s .
W eight (mg) c o n t r i b u t i o n to r
days 1 - 5 6 - 1 0 1 1 - 1 5
A p te r a e 2 .5 8 0 .7 2 15 . 6 5 3 .1 0
3 .5 BO.69 1 5 .7 4 3 .0 4
F l i e r s 2 .5 7B.12 1 6 .5 7 4 .9 6
3 .5 BO. 37 1 6 . 4 6 3 .0 3
N o n - f l i e r s 2 . 5 8 3 .2 8 1 4 .1 5 2 .3 6
3 .5 8 3 . 2 8 1 4 .1 4 2 . 3 6
16-20
36.
way a s f o r sm a l l and l a r g e a p t e r a e ( T ab le 14 ) .
A p o p u l a t i o n o f M. v i c i a e , a p t e r o u s o r a l a t e , w hich re m a in s
on th e o r i g i n a l h o s t p l a n t can m u l t i p l y i n u n i t t im e much f a s t e r
th a n a p o p u l a t i o n o f a l a t a e which f l y and c o l o n i s e a new h o s t
( T a b le 13 ) .
Sm all a l a t a e l o s e a b o u t 20$ o f t h e i r p o t e n t i a l l a r v a
p r o d u c t i o n i f th e y f l y ( T ab le 12 ) . A lthough t h i s i s l a r g e l y
co m p en sa ted f o r by th e d i s t r i b u t i o n i n t im e o f l a r v a p r o d u c t i o n
th e i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e o f a p o p u l a t i o n o f sm all
f l i e r s i s much lo w e r th a n th o s e o f p o p u l a t i o n s o f sm a l l a p t e r a e
and n o n - f l i e r s . L a r g e r a l a t a e l o s e o n ly 14$ o f t h e i r p o t e n t i a l
l a r v a p r o d u c t i o n i f th e y f l y ( T ab le 12 ) and t h e i r i n t r i n s i c
r a t e o f n a t u r a l i n c r e a s e i s a lm o s t a s h ig h ( 1 .4 0 ) a s t h a t o f
a p t e r a e ( 1 .4 1 and 1 .4 2 ) ( T ab le 13 ) . P o p u l a t i o n s o f n o n - f l ' i e r s
have a h i g h e r i n t r i n s i c r a t e o f n a t u r a l i n c r e a s e th a n th o s e o f
a p t e r a e ( T a b le 13 ) a l th o u g h t h e i r n e t r e p r o d u c t io n r a t e i s
lo w e r ( T a b le 12 ) .
P o p u l a t i o n s o f a l a t e M. v i c i a e can re p ro d u c e th e m s e lv e s i n
u n i t t im e l e s s o f t e n i f th e a l a t a e a r e sm all and have f low n
(A = 3 .7 4 ) C T a b le 13 ) th a n i f th e y a r e l a r g e and have flow n
( A = 4 .0 6 ) . I n th e l a t t e r c a s e th e y have a f i n i t e r a t e o f
i n c r e a s e A e q u a l to t h a t o f a p o p u la t io n o f a p t e r a e ( T a b le 13 ) .
A p o p u l a t i o n o f a l a t a e which h a s n o t f low n can m u l t i p l y i n u n i t
37.
t im e more th a n a p o p u l a t i o n o f a p t e r a e ( T ab le 13 ) . The
p h y s i o l o g i c a l s t a t e o f a l a t a e i s such t h a t i f a p o p u l a t i o n o f
a l a t a e d o es n o t f l y i t i s c a p a b le o f m u l t i p l y i n g i n u n i t t im e
much f a s t e r th a n a p o p u l a t i o n o f l a r g e a p t e r a e .
3(g). RESPIRATION RATES
I n h i b e r n a t i n g C o lo rado b e e t l e s , L e p t i n o t a r s a d e c e m l i n e a t a ,
r e s p i r a t i o n r a t e f a l l s , 75% of t h i s d e c r e a s e b e i n g due to th e
d e g e n e r a t i o n o f th e f l i g h t m u sc le s and t h e i r m i to c h o n d r i a
( S teg w ee , 1964 )• I n v iew o f t h i s and th e f a c t t h a t M. v i c i a e
a l a t a e l o s e t h e i r w ing m u sc le s th e r e s p i r a t i o n r a t e s o f f l i e r s
and n o n - f l i e r s m ig h t be q u i t e d i f f e r e n t from th o s e o f a p t e r a e
and from th o s e o f eac h o t h e r a t some s t a g e s i n t h e i r l i v e s .
o
The oxygen u p ta k e / h o u r by i n d i v i d u a l a p t e r a e , f l i e r s
and n o £ - f l i e r s was m easured u s i n g a c a p i l l a r y r e s p i r o m e t e r ( p . 11 )
A ph ids were r e s p i r e d a t d a i l y i n t e r v a l s from th e day a f t e r m ou lt
u n t i l some days a f t e r r e p r o d u c t i o n had s t a r t e d and th e l o g - l o g
r e l a t i o n s h i p be tw een p i oxygen consumed p e r a p h id p e r h o u r and
th e w e ig h t i n m i l l i g r a m s o f th e a p h id d e te rm in e d ( T ab le 15 )•
To make co m p ar iso n o f th e r e s u l t i n g r e g r e s s i o n l i n e s p o s s i b l e ,
t h e s e w ere r e c a l c u l a t e d u s i n g th e common r e g r e s s i o n c o e f f i c i e n t
f o r e a c h o f th e t h r e e g ro u p s ( F ig u r e 20, T a b le 16 ) . The
r e g r e s s i o n l i n e s f o r b o th a p t e r a e and n o n - f l i e r s a t th e s t a g e s
s t u d i e d w ere a l l s i m i l a r ( F = 2 . 4 0 2 , d . f . = 4 / 6 6 f o r n o n - f l i e r s ;
F = 2 .4 3 8 , d . f . = 4 /4 0 f o r a p t e r a e ) . When th e s lo p e s o f th e
r e g r e s s i o n l i n e s f o r f l i e r s were com pared, how ever, t h a t f o r
f l i e r s a b o u t to f l y had a c o m p le te ly d i f f e r e n t s lo p e from th e
o t h e r s ( F = 3 .4 7 2 , d . f . = 7 / U 2 , P 0 .0 1 f o r a l l l i n e s ; F = 1 .1 0 4
d . f . = 6 / 9 9 e x c l u d in g th o s e a b o u t to f l y ) .
T a b le 1 5 . R e g r e s s io n fo rm u la e f o r th e l o g . / l o g . r e l a t i o n s h i p o f
p i oxygen consumed / a n i m a l / h o u r on s u c c e s s iv e d ay s a f t e r th e
a d u l t m o u l t f o r a p t e r a e , f l i e r s and n o n - f l i e r s w i th th e s i g n i f i c a n c e
o f d e v i a t i o n from z e ro s lo p e o f t h e s e l i n e s and th e common
r e g r e s s i o n c o e f f i c i e n t c a l c u l a t e d f o r e ac h g ro u p .
Time
No. o f
a p h id s
S ig . o f d e v i a t i o n o f Common
R e g r e s s io n fo rm u la r e g r e s s i o n c o e f f . r e g r . from z e ro c o e f f .
Day a f t e r
m o u l t 10 Y = 0 .1 2 3 + 0 .974X 0 .0 0 1 0 .9 7 2
Two day s
a f t e r m o u l t 7 Y * 0 .6 6 6 + 0.915X 0 .0 5
1 s t day o f
r e p r o d u c t i o n 0 17 Y = 0 .4 1 2 + 0 .432X N. S.
2n d day o f
r e p r o d u c t i o n 10 Y « 0 .2 5 0 + O .686X 0 .1 0
4 t h day o f
r e p r o d u c t i o n Y = - 0 . 5 5 5 + I . 786X 0 . 0 1
F l i e r s
Day a f t e r
m o u l t 10 Y = 0 .1 0 0 + 1.103X 0 .0 0 1 0.726
A bout to
f l y * 15 Y = -O .O7O + 1 .7 3 1 X 0 .0 0 1
* n o t i n c l u d e d i n e s t i